Chemically amplified positive-type photosensitive resin composition

ABSTRACT

A chemically amplified positive-type photosensitive resin composition capable of forming a resist pattern having a nonresist portion with a favorable rectangular sectional shape, a method of manufacturing a resist pattern using the composition, a method of manufacturing a substrate with a template using the composition, and a method of manufacturing a plated article using the substrate with a template manufactured by the method. In a chemically amplified positive-type photosensitive resin composition including an acid generator, a resin whose solubility in alkali increases under the action of acid, and an organic solvent, an acrylic resin is used that includes a constituent unit derived from an acrylic acid ester including an —SO 2 -containing cyclic group or a lactone-containing cyclic group, and a constituent unit derived from an acrylic acid ester containing an organic group including an aromatic group and an alcoholic hydroxyl group.

RELATED APPLICATION

This application claims priority to Japanese Patent Application No.2016-091292 filed Apr. 28, 2016, the entire content of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a chemically amplified positive-typephotosensitive resin composition, a method of manufacturing a resistpattern using the chemically amplified positive-type photosensitiveresin composition, a method of manufacturing a substrate with a templateusing the chemically amplified positive-type photosensitive resincomposition, and a method of manufacturing a plated article using thesubstrate with a template manufactured by the method.

Related Art

Photofabrication is now the mainstream of a microfabrication technique.Photofabrication is a generic term describing the technology used formanufacturing a wide variety of precision components such assemiconductor packages. The manufacturing is carried out by applying aphotoresist composition to the surface of a processing target to form aphotoresist layer, patterning this photoresist layer usingphotolithographic techniques, and then conducting chemical etching,electrolytic etching, and/or electroforming based mainly onelectroplating, using the patterned photoresist layer (resist pattern)as a mask.

In recent years, high density packaging technologies have progressed insemiconductor packages along with downsizing electronics devices, andthe increase in package density has been developed on the basis ofmounting multi-pin thin film in packages, miniaturizing of package size,two-dimensional packaging technologies in flip-tip systems orthree-dimensional packaging technologies. In these types of high densitypackaging techniques, connection terminals, including protrudingelectrodes (mounting terminals) known as bumps that protrude above thepackage or metal posts that extend from peripheral terminals on thewafer and connect rewiring with the mounting terminals, are disposed onthe surface of the substrate with high precision.

In the photofabrication as described above, a photoresist composition isused, and chemically amplified photoresist compositions containing anacid generator have been known as such a photoresist composition, (seePatent Documents 1, 2 and the like). According to the chemicallyamplified photoresist composition, an acid is generated from the acidgenerator upon irradiation with radiation (exposure) and diffusion ofthe acid is promoted through heat treatment, to cause an acid catalyticreaction with a base resin and the like in the composition resulting ina change to the alkali-solubility of the same.

Further, photoresist compositions for use in the photofabrication arealso known (see, for example, Patent Document 3). Photoresistcompositions disclosed in Patent Document 3 are used, for example, inthe formation of bumps and metal posts by a plating step. For example, athick photoresist layer having a film thickness of about 20 μm is formedon a support, and the photoresist layer is exposed through apredetermined mask pattern and is developed. Thereby, a resist patternin which portions for forming bumps or metal posts have been selectivelyremoved (stripped) is formed. Then, bumps or metal posts can be formedby embedding a conductor such as copper into the removed portions(nonresist sections) using plating, and then removing the surroundingresidual resist pattern.

Patent Document 1: Japanese Unexamined Patent Application, PublicationNo. H9-176112

Patent Document 2: Japanese Unexamined Patent Application, PublicationNo. H11-052562

Patent Document 3: Japanese Unexamined Patent Application, PublicationNo. 2010-185986

SUMMARY OF THE INVENTION

For use in photofabrication applications as well as in other variousapplications, a resist pattern having a rectangular cross-sectionalshape at a portion removed upon development (nonresist section) isusually desired, in a case where the resist pattern is formed with aphotoresist composition for thick-film application.

Photoresist compositions as disclosed in Patent Document 3 are in manycases used as diluted with a solvent. The formation of a resist patternusing a solvent-containing photoresist composition, however, poses aproblem that, in a cross section of a resist pattern as observed from adirection perpendicular to a planar direction of the resist pattern, thewidth of a nonresist portion is likely to be narrowed by the protrusionof the resist portion towards the nonresist portion side around thesubstrate. Thus, the protrusion of the resist portion towards thenonresist portion side around the substrate is called “footing”. In thiscase, in the formation of bumps or metal posts using a resist pattern asa template, the area of contact between the formed bumps or metal postsand the substrate is so small that the bumps or the metal posts may fallor be separated from the substrate.

The present invention has been made in view of the above problems, andan object of the present invention is to provide a chemically amplifiedpositive-type photosensitive resin composition capable of forming aresist pattern having a nonresist portion with a favorable rectangularsectional shape, a method of manufacturing a resist pattern using thechemically amplified positive-type photosensitive resin composition, amethod of manufacturing a substrate with a template using the chemicallyamplified positive-type photosensitive resin composition, and a methodof manufacturing a plated article using the substrate with a templatemanufactured by the method.

The present inventors have found that the above problems can be solvedby using, in a chemically amplified positive-type photosensitive resincomposition comprising an (A) acid generator that produces an acid bybeing irradiated with an active ray or radiation, a (B) resin whosesolubility in alkali increases under the action of acid, and an (S)organic solvent, an (B-3) acrylic resin comprising a constituent unitderived from an acrylic acid ester comprising an —SO₂-containing cyclicgroup or a lactone-containing cyclic group, and a constituent unitderived from an acrylic acid ester containing an organic groupcomprising an aromatic group and an alcoholic hydroxyl group, which hasled to the completion of the present invention.

According to a first aspect of the present invention, there is provideda chemically amplified positive-type photosensitive resin composition,comprising an (A) acid generator that produces an acid by beingirradiated with an active ray or radiation, a (B) resin whose solubilityin alkali increases under the action of acid, and an (S) organicsolvent,

wherein the (B) resin whose solubility in alkali increases under theaction of acid contains an alkali-soluble group protected by analiphatic acid-dissociable dissolution-inhibiting group, andcomprises an (B-3) acrylic resin comprising a constituent unit derivedfrom an acrylic acid ester comprising an —SO₂-containing cyclic group ora lactone-containing cyclic group, and a constituent unit derived froman acrylic acid ester containing an organic group comprising an aromaticgroup and an alcoholic hydroxyl group.

According to a second aspect of the present invention, there is provideda method of manufacturing a resist pattern, comprising:

laminating a photosensitive resin layer on a substrate, the layercomprising the chemically amplified positive-type photosensitive resincomposition according to the first aspect of the present invention,exposing the photosensitive resin layer through irradiation with anactive ray or radiation, and developing the exposed photosensitivelayer.

According to a third aspect of the present invention, there is provideda method of manufacturing a substrate with a template, comprising:

laminating a photosensitive resin layer on a metal substrate, the layercomprising the chemically amplified positive-type photosensitive resincomposition according to the first aspect which is used for preparationof a template for plated article formation,exposing the photosensitive resin layer through irradiation with anactive ray or radiation, and developing the exposed photosensitive layerto prepare a template for plated article formation.

According to a fourth aspect of the present invention, there is provideda method of manufacturing a plated article, comprising plating thesubstrate with a template manufactured by the method according to thethird aspect to form the plated article inside the template.

The present invention can provide a chemically amplified positive-typephotosensitive resin composition capable of forming a resist patternhaving a nonresist portion with a favorable rectangular sectional shape,a method of manufacturing a resist pattern using the chemicallyamplified positive-type photosensitive resin composition, a method ofmanufacturing a substrate with a template using the chemically amplifiedpositive-type photosensitive resin composition, and a method ofmanufacturing a plated article using the substrate with a templatemanufactured by the method.

DETAILED DESCRIPTION OF THE INVENTION <<Chemically AmplifiedPositive-Type Photosensitive Resin Composition>>

The chemically amplified positive-type photosensitive resin composition(hereinafter also referred to as the “photosensitive resin composition”)contains an (A) acid generator capable of producing an acid whenirradiated with an active ray or radiation (hereinafter also referred toas the (A) acid generator), a (B) resin whose solubility in alkaliincreases under the action of acid (hereinafter also referred to as the(B) resin), and an (S) organic solvent. The photosensitive resincomposition may comprise one or more components selected from a (C)alkali-soluble resin and a (D) acid diffusion suppressing agent, ifdesired.

The layer thickness of the resist pattern formed using thephotosensitive resin composition is not particularly limited.Preferably, however, the photosensitive composition is preferably usedfor the formation of a thick resist pattern. The film thickness of aresist pattern formed with the photosensitive resin composition is 10 μmor more, preferably 10 to 150 μm, more preferably 20 to 120 μm, and inparticular preferably 20 to 100 μm.

<(A) Acid Generator>

The (A) acid generator is a compound capable of producing an acid whenirradiated with an active ray or radiation, and is not particularlylimited as long as it is a compound which directly or indirectlyproduces an acid under the action of light. The (A) acid generator ispreferably any one of the acid generators of the first to fifth aspectsthat will be described below. Hereinafter, suitable examples among the(A) acid generators that are suitably used in photosensitive resincompositions will be described as the first to fifth aspects.

The first aspect of the (A) acid generator may be a compound representedby the following formula (a1).

In the formula (a1), X^(1a) represents a sulfur atom or iodine atomrespectively having a valence of g; g represents 1 or 2. h representsthe number of repeating units in the structure within parentheses.R^(1a) represents an organic group that is bonded to X^(1a), andrepresents an aryl group having 6 to 30 carbon atoms, a heterocyclicgroup having 4 to 30 carbon atoms, an alkyl group having 1 to 30 carbonatoms, an alkenyl group having 2 to 30 carbon atoms, or an alkynyl grouphaving 2 to 30 carbon atoms, and R1a may be substituted with at leastone selected from the group consisting of an alkyl group, a hydroxylgroup, an alkoxy group, an alkylcarbonyl group, an arylcarbonyl group,an alkoxycarbonyl group, an aryloxycarbonyl group, an arylthiocarbonylgroup, an acyloxy group, an arylthio group, an alkylthio group, an arylgroup, a heterocyclic group, an aryloxy group, an alkylsulfinyl group,an arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, analkyleneoxy group, an amino group, a cyano group, a nitro group, andhalogen atoms. The number of R^(1a)s is g+h(g−1)+1, and the R^(1a)s maybe respectively identical to or different from each other. Furthermore,two or more R^(1a)s may be bonded to each other directly or via —O—,—S—, —SO—, —SO₂—, —NH—, —NR^(2a)—, —CO—, —COO—, —CONH—, an alkylenegroup having 1 to 3 carbon atoms, or a phenylene group, and may form aring structure containing X^(1a). R^(2a) represents an alkyl grouphaving 1 to 5 carbon atoms, or an aryl group having 6 to 10 carbonatoms.

X^(2a) represents a structure represented by the following formula (a2).

—X^(4a)X^(5a)—X^(4a)_(h)  (a2)

In the formula (a2) X^(4a) represents an alkylene group having 1 to 8carbon atoms, an arylene group having 6 to 20 carbon atoms, or adivalent group of a heterocyclic compound having 8 to 20 carbon atoms,and X^(4a) may be substituted with at least one selected from the groupconsisting of an alkyl group having 1 to 8 carbon atoms, an alkoxy grouphaving 1 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, ahydroxyl group, a cyano group, a nitro group, and halogen atoms. X^(5a)represents —O—,—S—,—SO—,—SO2-,—NH—,—NR^(2a)—,—CO—,—COO—,—CONH—, analkylene group having 1 to 3 carbon atoms, or a phenylene group.

h represents the number of repeating units of the structure inparentheses. X^(4a) s in the number of h+1 and X^(5a)s in the number ofh may be identical to or different from each other. R^(2a) has the samedefinition as described above.

X^(3a-) represents a counterion of an onium, and examples thereofinclude a fluorinated alkylfluorophosphoric acid anion represented bythe following formula (a17) or a borate anion represented by thefollowing formula (a18).

[(R^(3a))_(j)PF_(6-j)]⁻  (a17)

In the formula (a17), R^(3a) represents an alkyl group having 80% ormore of the hydrogen atoms substituted by fluorine atoms.

j represents the number of R^(3a)s and is an integer from 1 to 5.R^(3a)s in the number of j may be respectively identical to or differentfrom each other.

In the formula (a18) R^(4a) to R^(7a) each independently represents afluorine atom or a phenyl group, and a part or all of the hydrogen atomsof the phenyl group may be substituted by at least one selected from thegroup consisting of a fluorine atom and a trifluoromethyl group.

Examples of the onium ion in the compound represented by the formula(a1) include triphenylsulfonium, tri-p-tolylsulfonium,4-(phenylthio)phenyldiphenylsulfonium,bis[4-(diphenylsulfonio)phenyl]sulfide,bis[4-{bis[4-(2-hydroxyethoxy)phenyl]sulfonio}phenyl]sulfide,bis{4-[bis(4-fluorophenyl)sulfonio]phenyl}sulfide,4-(4-benzoyl-2-chlorophenylthio)phenylbis(4-fluorophenyl) sulfonium,7-isopropyl-9-oxo-10-thia-9,10-dihydroanthran-2-yldi-p-tolylsulfonium,7-isopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldiphenylsulfonium,2-[(diphenyl)sulfonio]thioxanthone,4-[4-(4-tert-butylbenzoyl)phenylthio]phenyldi-p-tolylsulfonium,4-(4-benzoylphenylthio)phenyldiphenylsulfonium,diphenylphenacylsulfonium, 4-hydroxyphenylmethylbenzylsulfo-nium,2-naphthylmethyl(1-ethoxycarbonyl)ethylsulfonium,4-hydroxyphenylmethylphenacylsulfonium,phenyl[4-(4-biphenylthio)phenyl]-4-biphenylsulfonium,phenyl[4-(4-biphenylthio)phenyl]-3-biphenylsulfonium,[4-(4-acetophenylthio)phenyl]diphenylsulfonium,octadecylmethylphenacylsulfonium, diphenyliodonium, di-p-tolyliodonium,bis(4-dodecylphenyl)iodonium, bis(4-methoxyphenyl)iodonium,(4-octyloxyphenyl)phenyliodonium, bis(4-decyloxy)phenyliodonium,4-(2-hydroxytetradecyloxy)phenylphenyliodonium,4-isopropylphenyl(p-tolyl)iodonium, and4-isobutylphenyl(p-tolyl)iodonium.

Among the onium ions in the compound represented by the formula (a1), apreferred onium ion may be a sulfonium ion represented by the followingformula (a19).

In the formula (a19), R^(8a)s each independently represents a hydrogenatom or a group selected from the group consisting of alkyl, hydroxyl,alkoxy, alkylcarbonyl, alkylcarbonyloxy, alkyloxycarbonyl, a halogenatom, an aryl, which may be substituted, and arylcarbonyl. X^(2a) hasthe same definition as X^(2a) in the formula (a1).

Specific examples of the sulfonium ion represented by the formula (a19)include 4-(phenylthio)phenyldiphenylsulfonium,4-(4-benzoyl-2-chlorophenylthio)phenylbis(4-fluorophenyl) sulfonium,4-(4-benzoylphenylthio)phenyldiphenylsulfonium,phenyl[4-(4-biphenylthio)phenyl]-4-biphenylsulfonium,phenyl[4-(4-biphenylthio)phenyl]-3-biphenylsulfonium,[4-(4-acetophenylthio)phenyl]diphenylsulfonium, anddiphenyl[4-(p-terphenylthio) phenyl]diphenylsulfonium.

In regard to the fluorinated alkylfluorophosphoric acid anionrepresented by the formula (a17), R^(3a) represents an alkyl groupsubstituted with a fluorine atom, and a preferred number of carbon atomsis 1 to 8, while a more preferred number of carbon atoms is 1 to 4.Specific examples of the alkyl group include linear alkyl groups such asmethyl, ethyl, propyl, butyl, pentyl and octyl; branched alkyl groupssuch as isopropyl, isobutyl, sec-butyl and tert-butyl; and cycloalkylgroups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl. Theproportion of hydrogen atoms substituted by fluorine atoms in the alkylgroups is usually 80% or more, preferably 90% or more, and even morepreferably 100%. If the substitution ratio of fluorine atoms is lessthan 80%, the acid strength of the onium fluorinatedalkylfluorophosphate represented by the formula (a1) decreases.

A particularly preferred example of R^(3a) is a linear or branchedperfluoroalkyl group having 1 to 4 carbon atoms and a substitution ratioof fluorine atoms of 100%. Specific examples thereof include CF₃,CF₃CF₂, (CF₃)₂CF, CF₃CF₂CF₂, CF₃CF₂CF₂CF₂, (CF₃)₂CFCF₂, CF₃CF₂ (CF₃) CF,and (CF₃)₃C. j which is the number of R^(3a)s represents an integer from1 to 5, and is preferably 2 to 4, and particularly preferably 2 or 3.

Preferred specific examples of the fluorinated alkylfluorophosphoricacid anion include [(CF₃CF₂)₂PF₄], [(CF₃CF₂)₃PF₃]⁻, [((CF₃)₂CF)₂PF₄]⁻,[((CF₃)₂CF)₃PF₃]⁻, [(CF₃CF₂CF₂)₂PF₄]⁻, [(CF₃CF₂CF₂)₃PF₃]⁻,[((cF₃)₂CFCF₂)₂PF₄]⁻, [((CF₃)₂CFCF₂)₃PF₃]⁻, [(CF₃CF₂CF₂CF₂)₂PF₄]⁻, and[(CF₃CF₂CF₂)₃PF₃]⁻. Among these, [(CF₃CF₂)₃PF₃]⁻, [(CF₃CF₂CF₂)₃PF₃]⁻,[((CF₃)₂CF)₃PF₃]⁻, [((CF₃)₂CF)₂PF₄]⁻, [((CF₃)₂CFCF₂)₃PF₃]⁻, and[((CF₃)₂CFCF₂)₂PF₄]⁻ are particularly preferred.

Preferred specific examples of the borate anion represented by theformula (a18) include tetrakis(pentafluorophenyl)borate ([B(C₆F₅)₄]⁻),tetrakis[(trifluoromethyl)phenyl]borate ([B(C₆H₄CF₃)₄]⁻),difluorobis(pentafluorophenyl)borate ([(C₆F₅)₂BF₂]⁻),trifluoro(pentafluorophenyl)borate ([(C₆F₅)BF₃]⁻), andtetrakis(difluorophenyl)borate ([B(C₆H₃F₂)₄]⁻). Among these,tetrakis(pentafluorophenyl)borate ([B(C₆F₅)₄]⁻) is particularlypreferred.

The second aspect of the (A) acid generator include halogen-containingtriazine compounds such as2,4-bis(trichloromethyl)-6-piperonyl-1,3,5-triazine,2,4-bis(trichloromethyl)-6-[2-(2-furyl)ethenyl]-s-triazine,2,4-bis(trichloromethyl)-6-[2-(5-methyl-2-furyl)ethenyl]-s-triazine,2,4-bis(trichloromethyl)-6-[2-(5-ethyl-2-furyl)ethenyl]-s-triazine,2,4-bis(trichloromethyl)-6-[2-(5-propyl-2-furyl)ethenyl]-s-triazine,2,4-bis(trichloromethyl)-6-[2-(3,5-dimethoxyphenyl)ethenyl]-s-triazine,2,4-bis(trichloromethyl)-6-[2-(3,5-diethoxyphenyl)ethenyl]-s-triazine,2,4-bis(trichloromethyl)-6-[2-(3,5-dipropoxyphenyl)ethenyl]-s-triazine,2,4-bis(trichloromethyl)-6-[2-(3-methoxy-5-ethoxyphenyl)ethenyl]-s-triazine,2,4-bis(trichloromethyl)-6-[2-(3-methoxy-5-propoxyphenyl)ethenyl]-s-triazine,2,4-bis(trichloromethyl)-6-[2-(3,4-methylenedioxyphenyl)ethenyl]-s-triazine,2,4-bis(trichloromethyl)-6-(3,4-methylenedioxyphenyl)-s-triazine,2,4-bis-trichloromethyl-6-(3-bromo-4-methoxy)phenyl-s-triazine,2,4-bis-trichloromethyl-6-(2-bromo-4-methoxy)phenyl-s-triazine,2,4-bis-trichloromethyl-6-(2-bromo-4-methoxy)styrylphenyl-s-triazine,2,4-bis-trichloromethyl-6-(3-bromo-4-methoxy)styrylphenyl-s-triazine,2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine,2-(4-methoxynaphthyl)-4,6-bis(trichloromethyl)-1,3,5-triazine,2-[2-(2-furyl)ethenyl]-4,6-bis(trichloromethyl)-1,3,5-triazine,2-[2-(5-methyl-2-furyl)ethenyl]-4,6-bis(trichloromethyl)-1,3,5-triazine,2-[2-(3,5-dimethoxyphenyl)ethenyl]-4,6-bis(trichloromethyl)-1,3,5-triazine,2-[2-(3,4-dimethoxyphenyl)ethenyl]-4,6-bis(trichloromethyl)-1,3,5-triazine,2-(3,4-methylenedioxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine,tris(1,3-dibromopropyl)-1,3,5-triazine andtris(2,3-dibromopropyl)-1,3,5-triazine, and halogen-containing triazinecompounds represented by the following formula (a3) such astris(2,3-dibromopropyl)isocyanurate.

In the formula (a3), R^(9a), R^(10a) and R^(11a) each independentlyrepresent a halogenated alkyl group.

Further, the third aspect of the (A) acid generator includeα-(p-toluenesulfonyloxyimino)-phenylacetonitrile,α-(benzenesulfonyloxyimino)-2,4-dichlorophenylacetonitrile,α-(benzenesulfonyloxyimino)-2,6-dichlorophenylacetonitrile,α-(2-chlorobenzenesulfonyloxyimino)-4-methoxyphenylacetonitrile andα-(ethylsulfonyloxyimino)-1-cyclopentenylacetonitrile, and compoundsrepresented by the following formula (a4) having an oximesulfonategroup.

In the formula (a4), R^(12a) represents a monovalent, bivalent ortrivalent organic group, R^(13a) represents a substituted orunsubstituted saturated hydrocarbon group, an unsaturated hydrocarbongroup, or an aromatic compound group, and n represents the number ofrepeating units of the structure in the parentheses.

In the formula (a4), the aromatic compound group indicates a group ofcompounds having physical and chemical properties characteristic ofaromatic compounds, and examples thereof include aryl groups such as aphenyl group and a naphthyl group, and heteroaryl groups such as a furylgroup and a thienyl group may be exemplified. These may have one or moreappropriate substituents such as halogen atoms, alkyl groups, alkoxygroups and nitro groups on the rings. It is particularly preferable thatR^(13a) is an alkyl group having 1 to 6 carbon atoms such as a methylgroup, an ethyl group, a propyl group, and a butyl group. In particular,compounds in which R^(12a) represents an aromatic compound group, andR^(13a) represents an alkyl group having 1 to 4 carbon atoms arepreferred.

Examples of the acid generator represented by the formula (a4), includecompounds in which R^(12a) is any one of a phenyl group, a methylphenylgroup and a methoxyphenyl group, and R^(13a) is a methyl group, providedthat n is 1, and specific examples thereof includeα-(methylsulfonyloxyimino)-1-phenylacetonitrile,α-(methylsulfonyloxyimino)-1-(p-methylphenyl)acetonitrile,α-(methylsulfonyloxyimino)-1-(p-methoxyphenyl)acetonitrile,[2-(propylsulfonyloxyimino)-2,3-dihydroxythiophene-3-ylidene](o-tolyl)acetonitrileand the like. Provided that n is 2, the acid generator represented bythe formula (a4) is specifically an acid generator represented by thefollowing formulae.

In addition, the fourth aspect of the (A) acid generator include oniumsalts that have a naphthalene ring at their cation moiety. Theexpression “have a naphthalene ring” indicates having a structurederived from naphthalene and also indicates at least two ring structuresand their aromatic properties are maintained. The naphthalene ring mayhave a substituent such as a linear or branched alkyl group having 1 to6 carbon atoms, a hydroxyl group, a linear or branched alkoxy grouphaving 1 to 6 carbon atoms or the like. The structure derived from thenaphthalene ring, which may be of a monovalent group (one free valance)or of a bivalent group (two free valences), is desirably of a monovalentgroup (in this regard, the number of free valance is counted except forthe portions connecting with the substituents described above). Thenumber of naphthalene rings is preferably 1 to 3.

Preferably, the cation moiety of the onium salt having a naphthalenering at the cation moiety is of the structure represented by thefollowing general formula (a5).

In the formula (a5), at least one of R^(14a), R^(15a) and R^(16a)represents a group represented by the following formula (a6), and theremaining represents a linear or branched alkyl group having 1 to 6carbon atoms, a phenyl group which may have a substituent, a hydroxylgroup, or a linear or branched alkoxy group having 1 to 6 carbon atoms.Alternatively, one of R^(14a), R^(15a) and R^(16a) is a grouprepresented by the following formula (a6), and the remaining two areeach independently a linear or branched alkylene group having 1 to 6carbon atoms, and these terminals may bond to form a ring structure.

In the formula (a6), R^(17a) and R^(18a) each independently represent ahydroxyl group, a linear or branched alkoxy group having 1 to 6 carbonatoms, or a linear or branched alkyl group having 1 to 6 carbon atoms,and R^(19a) represents a single bond or a linear or branched alkylenegroup having 1 to 6 carbon atoms that may have a substituent.

l and m each independently represent an integer of 0 to 2, and l+m is nogreater than 3. In this regard, when there exists a plurality ofR^(17a), they may be identical or different from each other.Furthermore, when there exist a plurality of R^(18a), they may beidentical or different from each other.

Preferably, among R^(14a), R^(15a) and R^(16a) as above, the number ofgroups represented by the formula (a6) is one in view of the stabilityof the compound, and the remaining are linear or branched alkylenegroups having 1 to 6 carbon atoms of which the terminals may bond toform a ring. In this case, the two alkylene groups described above forma 3 to 9 membered ring including sulfur atom(s). Preferably, the numberof atoms to form the ring (including sulfur atom(s)) is 5 or 6.

The substituent, which the alkylene group may have, is exemplified by anoxygen atom (in this case, a carbonyl group is formed together with acarbon atom that constitutes the alkylene group), a hydroxyl group orthe like.

Alternatively, the substituent, which the phenyl group may have, isexemplified by a hydroxyl group, a linear or branched alkoxy groupshaving 1 to 6 carbon atoms, linear or branched alkyl groups having 1 to6 carbon atoms, or the like.

Examples of suitable cation moiety include those represented by thefollowing formulae (a7) and (a8), and the structure represented by thefollowing formula (a8) is particularly preferable.

The cation moieties, which may be of an iodonium salt or a sulfoniumsalt, are desirably of a sulfonium salt in view of acid-producingefficiency.

It is, therefore, desirable that the preferable anion moiety of theonium salt having a naphthalene ring at the cation moiety is an anioncapable of forming a sulfonium salt.

The anion moiety of the acid generator is exemplified byfluoroalkylsulfonic acid ions, of which hydrogen atom(s) being partiallyor entirely fluorinated, or aryl sulfonic acid ions.

The alkyl group of the fluoroalkylsulfonic acid ions may be linear,branched or cyclic and have 1 to 20 carbon atoms. Preferably, the carbonnumber is 1 to 10 in view of bulkiness and diffusion distance of theproduced acid. In particular, branched or cyclic groups are preferabledue to shorter diffusion length. Also, methyl, ethyl, propyl, butyl,octyl groups and the like are preferable due to being inexpensivelysynthesizable.

The aryl group of the aryl sulfonic acid ions may be an aryl grouphaving 6 to 20 carbon atoms, and is exemplified by a phenol group or anaphthyl group that may be unsubstituted or substituted with an alkylgroup or a halogen atom. In particular, aryl groups having 6 to 10carbon atoms are preferred since they can be synthesized inexpensively.Specific examples of preferable aryl group include phenyl,toluenesulfonyl, ethylphenyl, naphthyl, methylnaphthyl groups and thelike.

When hydrogen atoms in the fluoroalkylsulfonic acid ion or the arylsulfonic acid ion are partially or entirely substituted with a fluorineatom, the fluorination rate is preferably 10% to 100%, and morepreferably 50% to 100%; it is particularly preferable that all hydrogenatoms are each substituted with a fluorine atom in view of higher acidstrength. Specific examples thereof include trifluoromethane sulfonate,perfluorobutane sulfonate, perfluorooctane sulfonate, perfluorobenzenesulfonate, and the like.

Among these, the preferable anion moiety is exemplified by thoserepresented by the following formula (a9).

R^(20a)SO₃ ⁻  (a9)

In the formula (a9), R^(20a) represents a group represented by thefollowing formula (a10) or (a11), or a group represented by thefollowing formula (a12).

In the formula (a10), x represents an integer of 1 to 4. Also, in theformula (a11), R21a represents a hydrogen atom, a hydroxyl group, alinear or branched alkyl group having 1 to 6 carbon atoms, or a linearor branched alkoxy group having 1 to 6 carbon atoms, and y represents aninteger of 1 to 3. Of these, trifluoromethane sulfonate, andperfluorobutane sulfonate are preferable in view of safety.

In addition, a nitrogen-containing moiety represented by the followingformula (a13) or (a14) may be also be used for the anion moiety.

In the formulae (a13) and (a14), X^(a) represents a linear or branchedalkylene group of which at least one hydrogen atom is substituted with afluorine atom, the carbon number of the alkylene group is 2 to 6,preferably 3 to 5, and most preferably the carbon number is 3. Inaddition, Y^(a) and Z^(a) each independently represent a linear orbranched alkyl group of which at least one hydrogen atom is substitutedwith a fluorine atom, the number of carbon atoms of the alkyl group is 1to 10, preferably 1 to 7, and more preferably 1 to 3.

The smaller number of carbon atoms in the alkylene group of X^(a), or inthe alkyl group of Y^(a) or Z^(a) is preferred since the solubility intoorganic solvent is favorable.

In addition, a larger number of hydrogen atoms each substituted by afluorine atom in the alkylene group of X^(a), or in the alkyl group ofY^(a) or Z^(a) is preferred since the acid strength becomes greater. Thepercentage of fluorine atoms in the alkylene group or alkyl group, i.e.,the fluorination rate is preferably 70 to 100% and more preferably 90 to100%, and most preferable are perfluoroalkylene or perfluoroalkyl groupsin which all of the hydrogen atoms are each substituted with a fluorineatom.

Preferable onium salts having a naphthalene ring at their cationmoieties are exemplified by compounds represented by the followingformulae (a15) and (a16).

Also, the fifth aspect of the (A)acid generator includebissulfonyldiazomethanes such as bis(p-toluenesulfonyl)diazomethane,bis(1,1-dimethyl ethylsulfonyl)diazomethane,bis(cyclohexylsulfonyl)diazomethane andbis(2,4-dimethylphenylsulfonyl)diazomethane; nitrobenzyl derivativessuch as 2-nitrobenzyl p-toluenesulfonate, 2,6-dinitrobenzylp-toluenesulfonate, nitrobenzyl tosylate, dinitrobenzyl tosylate,nitrobenzyl sulfonate, nitrobenzyl carbonate and dinitrobenzylcarbonate; sulfonates such as pyrogalloltrimesylate,pyrogalloltritosylate, benzyltosylate, benzylsulfonate,N-methylsulfonyloxysuccinimide, N-trichloromethylsulfonyloxysuccinimide,N-phenylsulfonyloxymaleimide and N-methylsulfonyloxyphthalimide;trifluoromethane sulfonates such as N-hydroxyphthalimide andN-hydroxynaphthalimide; onium salts such as diphenyliodoniumhexafluorophosphate, (4-methoxyphenyl)phenyliodoniumtrifluoromethanesulfonate, bis(p-tert-butylphenyl)iodoniumtrifluoromethanesulfonate, triphenylsulfonium hexafluorophosphate,(4-methoxyphenyl)diphenylsulfonium trifluoromethanesulfonate and(p-tert-butylphenyl) diphenylsulfonium trifluoromethanesulfonate;benzointosylates such as benzointosylate and α-methylbenzointosylate;other diphenyliodonium salts, triphenylsulfonium salts, phenyldiazoniumsalts, benzylcarbonates and the like.

This (A) acid generator may be used alone, or two or more kinds may beused in combination. Furthermore, the content of the (A) acid generator(A) is preferably adjusted to 0.1% to 10% by mass, and more preferably0.5% to 3% by mass, relative to the total mass of the photosensitiveresin composition. When the amount of the acid generator (A) used isadjusted to the range described above, a photosensitive resincomposition that is a uniform solution having satisfactory sensitivityand exhibiting excellent storage stability can be readily prepared.

<(B) Resin>

The (B) resin whose solubility in alkali increases under the action ofacid contains an alkali-soluble group protected by an aliphaticacid-dissociable dissolution-inhibiting group and comprises an (B-3)acrylic resin comprising a constituent unit derived from an acrylic acidester comprising an —SO₂-containing cyclic group or a lactone-containingcyclic group, and a constituent unit derived from an acrylic acid estercontaining an organic group comprising an aromatic group and analcoholic hydroxyl group (hereinafter referred to also as “(B-3) acrylicresin”). When the photosensitive resin composition contains an (B-3)acrylic resin, a resist pattern having a favorable rectangular sectionalshape can be formed. Note that the (B) resin whose solubility in alkaliincreases under the action of acid may comprise a resin other than theabove (B-3) acrylic resin conventionally blended in a positive-typephotosensitive resin composition.

The content of the (B-3) acrylic resin in the total resin componentscontained in a photosensitive resin composition is preferably 70% bymass or more, preferably 90% by mass or more, and more preferably 100%by mass relative to the total mass of the (B) resin whose solubility inalkali increases under the action of acid and a (C) alkali-soluble resindescribed below.

Below, as preferred examples of the (B) resin whose solubility in alkaliincreases under the action of acid, a (B1) novolak resin, a (B-2)polyhydroxystyrene resin and an (B3) acrylic resin (B3) will bedescribed in this order.

[(B1) Novolak Resin]

As the (B1) novolak resin, a resin including the structural unitrepresented by the following general formula (b1) may be used.

In the formula (b1), R^(1b) represents an acid-dissociabledissolution-inhibiting group, and R^(2b) and R^(3b) each independentlyrepresent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

The acid-dissociable dissolution-inhibiting group represented by theabove R^(1b) is preferably a group represented by the following formula(b2) or (b3), a linear, branched or cyclic alkyl group having 1 to 6carbon atoms, a vinyloxyethyl group, a tetrahydropyranyl group, atetrahydrofuranyl group, or a trialkylsilyl group.

In the formulae (b2) and (b3), R^(4b) and R^(5b) each independentlyrepresent a hydrogen atom, or a linear or branched alkyl group having 1to 6 carbon atoms, R^(6b) represents a linear, branched or cyclic alkylgroup having 1 to 10 carbon atoms, R^(7b) represents a linear, branchedor cyclic alkyl group having 1 to 6 carbon atoms, and o represents 0 or1.

Examples of the linear or branched alkyl group include a methyl group,an ethyl group, a propyl group, an isopropyl group, a n-butyl group, anisobutyl group, a tert-butyl group, a pentyl group, an isopentyl group,a neopentyl group, and the like. Also, examples of the cyclic alkylgroup include a cyclopentyl group, a cyclohexyl group, and the like.

Specific examples of the acid-dissociable dissolution-inhibiting grouprepresented by the formula (b2) include a methoxyethyl group,ethoxyethyl group, n-propoxyethyl group, isopropoxyethyl group,n-butoxyethyl group, isobutoxyethyl group, tert-butoxyethyl group,cyclohexyloxyethyl group, methoxypropyl group, ethoxypropyl group,1-methoxy-1-methyl-ethyl group, 1-ethoxy-1-methylethyl group, and thelike. Furthermore, specific examples of the acid-dissociabledissolution-inhibiting group represented by the formula (b3) include atert-butoxycarbonyl group, tert-butoxycarbonylmethyl group, and thelike. Examples of the trialkylsilyl group include a trimethylsilyl groupand tri-tert-butyldimethylsilyl group in which each alkyl group has 1 to6 carbon atoms.

[(B2) Polyhydroxystyrene Resin]

As the (B2) polyhydroxystyrene resin, a resin including the structuralunit represented by the following formula (b4) may be used.

In the formula (b4), R^(8b) represents a hydrogen atom or an alkyl grouphaving 1 to 6 carbon atoms, and R^(9b) represents an acid-dissociabledissolution-inhibiting group.

The alkyl group having 1 to 6 carbon atoms may include, for example,linear, branched or cyclic alkyl groups having 1 to 6 carbon atoms.Examples of the linear or branched alkyl group include a methyl group,ethyl group, propyl group, isopropyl group, n-butyl group, isobutylgroup, tert-butyl group, pentyl group, isopentyl group and neopentylgroup, and examples of the cyclic alkyl group include a cyclopentylgroup and cyclohexyl group.

The acid-dissociable dissolution-inhibiting group represented by theabove R^(9b) may be similar to the acid-dissociabledissolution-inhibiting groups exemplified in terms of the above formulae(b2) and (b3).

Furthermore, the (B2) polyhydroxystyrene resin may include anotherpolymerizable compound as a structural unit in order to moderatelycontrol physical or chemical properties. The polymerizable compound isexemplified by conventional radical polymerizable compounds and anionpolymerizable compounds. Examples of the polymerizable compound includemonocarboxylic acids such as acrylic acid, methacrylic acid and crotonicacid; dicarboxylic acids such as maleic acid, fumaric acid and itaconicacid; methacrylic acid derivatives having a carboxyl group and an esterbond such as 2-methacryloyloxyethyl succinic acid,2-methacryloyloxyethyl maleic acid 2-methacryloyloxyethyl phthalic acidand 2-methacryloyloxyethyl hexahydrophthalic acid; (meth)acrylic acidalkyl esters such as methyl(meth)acrylate, ethyl (meth)acrylate andbutyl (meth)acrylate; (meth)acrylic acid hydroxyalkyl esters such as2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate;(meth)acrylic acid aryl esters such as phenyl (meth)acrylate and benzyl(meth)acrylate; dicarboxylic acid diesters such as diethyl maleate anddibutyl fumarate; vinyl group-containing aromatic compounds such asstyrene, α-methylstyrene, chlorostyrene, chloromethylstyrene,vinyltoluene, hydroxystyrene, α-methylhydroxystyrene andα-ethylhydroxystyrene; vinyl group-containing aliphatic compounds suchas vinyl acetate; conjugated diolefins such as butadiene and isoprene;nitrile group-containing polymerizable compounds such as acrylonitrileand methacrylonitrile; chlorine-containing polymerizable compounds suchas vinyl chloride and vinylidene chloride; and amide bond-containingpolymerizable compounds such as acrylamide and methacrylamide.

[(B3) Acrylic Resin]

As described above, the photosensitive resin composition indispensablycontains an (B-3) acrylic resin comprising a constituent unit derivedfrom an acrylic acid ester comprising an —SO₂-containing cyclic group ora lactone-containing cyclic group, and a constituent unit derived froman acrylic acid ester containing an organic group comprising an aromaticgroup and an alcoholic hydroxyl group. Accordingly, the (B3) acrylicresin is preferably an (B-3) acrylic resin comprising a constituent unitderived from an acrylic acid ester comprising an —SO₂-containing cyclicgroup or a lactone-containing cyclic group, and a constituent unitderived from an acrylic acid ester containing an organic groupcomprising an aromatic group and an alcoholic hydroxyl group. The (B-3)acrylic resin that is a preferred resin will be described as a preferred(B3) acrylic resin.

(B-3) Acrylic Resin

The (B-3) acrylic resin comprises a constituent unit derived from anacrylic acid ester comprising an —SO₂-containing cyclic group or alactone-containing cyclic group, and a constituent unit derived from anacrylic acid ester containing an organic group comprising an aromaticgroup and an alcoholic hydroxyl group. Accordingly, the (B-3) acrylicresin indispensably contains a constituent unit (b-3a) comprising an—SO₂-containing cyclic group or a lactone-containing cyclic group, and aconstituent unit (b-3b) comprising an organic group comprising anaromatic group and an alcoholic hydroxyl group.

(Constituent Unit (b-3a))

The constituent unit (b-3a) comprising an —SO₂-containing cyclic groupor a lactone-containing cyclic group will be described. In this case,the “—SO₂-containing cyclic group” refers to a cyclic group having acyclic group containing a ring comprising —SO₂— in the ring backbonethereof, specifically a cyclic group in which the sulfur atom (S) in—SO₂— forms a part of the ring backbone of the cyclic group. Consideringa ring comprising —SO₂— in the ring backbone thereof as the first ring,a group having that ring alone is called a monocyclic group, and a groupfurther having another ring structure is called a polycyclic groupregardless of its structure. The —SO₂-containing cyclic group may bemonocyclic or polycyclic.

In particular, the —SO₂-containing cyclic group is preferably a cyclicgroup containing —O—SO₂— in the ring backbone thereof, i.e., a cyclicgroup containing a sultone ring in which —O—S— in —O—SO₂— forms a partof the ring backbone.

The number of carbon atoms in an —SO₂-containing cyclic group ispreferably 3 to 30, more preferably 4 to 20, even more preferably 4 to15, and in particular preferably 4 to 12. The above number of carbonatoms is the number of carbon atoms constituting a ring backbone, andshall not include the number of carbon atoms in a substituent.

The —SO₂-containing cyclic group may be an —SO₂-containing aliphaticcyclic group or an —SO₂-containing aromatic cyclic group. It ispreferably an —SO₂-containing aliphatic cyclic group.

—SO₂-containing aliphatic cyclic groups include a group in which atleast one hydrogen atom is removed from an aliphatic hydrocarbon ringwhere a part of the carbon atoms constituting the ring backbone thereofis(are) substituted with —SO₂— or —O—SO₂. More specifically, theyinclude a group in which at least one hydrogen atom is removed from analiphatic hydrocarbon ring where —CH₂— constituting the ring backbonethereof is substituted with —SO₂— and a group in which at least onehydrogen atom is removed from an aliphatic hydrocarbon ring where—CH₂—CH₂— constituting the ring backbone thereof is substituted with—O—SO₂—.

The number of carbon atoms in the above alicyclic hydrocarbon ring ispreferably 3 to 20, more preferably 3 to 12. The above alicyclichydrocarbon ring may be polycyclic, or may be monocyclic. As themonocyclic alicyclic hydrocarbon group, preferred is a group in whichtwo hydrogen atoms are removed from monocycloalkane having 3 to 6 carbonatoms. Examples of the above monocycloalkane can include cyclopentane,cyclohexane and the like. As the polycyclic alicyclic hydrocarbon ring,preferred is a group in which two hydrogen atoms are removed frompolycycloalkane having 7 to 12 carbon atoms, and specific examples ofthe above polycycloalkane include adamantane, norbornane, isobornane,tricyclodecane, tetracyclododecane and the like.

The —SO₂-containing cyclic group may have a substituent. Examples of theabove substituent include, for example, an alkyl group, an alkoxy group,a halogen atom, a halogenated alkyl group, a hydroxy group, an oxygenatom (═O), —COOR″, —OC(═O)R″, a hydroxyalkyl group, a cyano group andthe like.

For an alkyl group as the above substituent, preferred is an alkyl grouphaving 1 to 6 carbon atoms. The above alkyl group is preferably linearor branched. Specific examples include a methyl group, an ethyl group,an n-propyl group, an isopropyl group, an n-butyl group, an isobutylgroup, a tert-butyl group, an n-pentyl group, an isopentyl group, aneopentyl group, an n-hexyl group and the like. Among these, a methylgroup or an ethyl group is preferred, and in particular a methyl groupis preferred.

For an alkoxy group as the above substituent, preferred is an alkoxygroup having 1 to 6 carbon atoms. The above alkoxy group is preferablylinear or branched. Specific examples include a group in which an alkylgroups recited as an alkyl group for the above substituent is attachedto the oxygen atom (—O—).

Halogen atoms as the substituent include a fluorine atom, a chlorineatom, a bromine atom, an iodine atom and the like, and a fluorine atomis preferred.

Halogenated alkyl groups for the above substituent include a group inwhich a part or all of the hydrogen atoms in the above alkyl groupis(are) substituted with the above halogen atom(s).

Halogenated alkyl groups as the above substituent include a group inwhich a part or all of the hydrogen atoms in the alkyl groups recited asan alkyl group for the above substituent is(are) substituted with theabove halogen atom(s). As the above halogenated alkyl group, afluorinated alkyl group is preferred, and a perfluoroalkyl group isparticularly preferred.

R″s in the aforementioned —COOR″ and —OC(═O)R″ are either a hydrogenatom or a linear, branched or cyclic alkyl group having 1 to 15 carbonatoms.

In a case where R″ is a linear or branched alkyl group, the number ofcarbon atoms in the above chain alkyl group is preferably 1 to 10, morepreferably 1 to 5, and in particular preferably 1 or 2.

In a case where R″ is a cyclic alkyl group, the number of carbon atomsin the above cyclic alkyl group is 3 to 15, more preferably 4 to 12, andin particular preferably 5 to 10. Specific examples can include a groupin which one or more hydrogen atoms are removed from monocycloalkane;and polycycloalkane such as bicycloalkane, tricycloalkane,tetracycloalkane, which are optionally substituted with a fluorine atomor a fluorinated alkyl group. More specific examples include a group inwhich one or more hydrogen atoms are removed from monocycloalkane suchas cyclopentane and cyclohexane; and polycycloalkane such as adamantane,norbornane, isobornane, tricyclodecane and tetracyclododecane.

For a hydroxyalkyl group as the above substituent, preferred is ahydroxyalkyl group having 1 to 6 carbon atoms. Specific examples includea group in which at least one of the hydrogen atoms in the alkyl groupsrecited as an alkyl group for the above substituent is substituted witha hydroxy group.

More specific examples of the —SO₂-containing cyclic group include thegroups represented by the following formulae (3-1) to (3-4).

(In the formulae, A′ represents an alkylene group having 1 to 5 carbonatoms optionally comprising an oxygen atom or a sulfur atom, an oxygenatom or a sulfur atom; z represents an integer of 0 to 2; R^(10b)represents an alkyl group, an alkoxy group, a halogenated alkyl group, ahydroxy group, —COOR″, —OC(═O)R″, a hydroxyalkyl group, or a cyanogroup; and R″ represents a hydrogen atom or an alkyl group.)

In the above formulae (3-1) to (3-4), A′ represents an alkylene grouphaving 1 to 5 carbon atoms optionally comprising an oxygen atom (—O—) ora sulfur atom (—S—), an oxygen atom or a sulfur atom. As an alkylenegroup having 1 to 5 carbon atoms in A′, a linear or branched alkylenegroup is preferred, including a methylene group, an ethylene group, ann-propylene group, an isopropylene group and the like.

In a case where the above alkylene group comprises an oxygen atom or asulfur atom, specific examples thereof include a group in which —O— or—S— is present at a terminal or between carbon atoms of the abovealkylene group, for example, —O—CH₂—, —CH₂—O—CH₂—, —S—CH₂—, —CH₂—S—CH₂—,and the like. As A′, an alkylene group having 1 to 5 carbon atoms or —O—is preferred, and an alkylene group having 1 to 5 carbon atoms is morepreferred, and a methylene group is most preferred.

z may be any of 0 to 2, and is most preferably 0. In a case where z is2, more than one R^(10b) may be the same, or may differ from each other.

Examples of an alkyl group, an alkoxy group, a halogenated alkyl group,—COOR″, —OC(═O)R″ and a hydroxyalkyl group in R^(10b) include thosesimilar to the groups described for the alkyl group, the alkoxy group,the halogenated alkyl group, —COOR″, —OC(═O)R″ and the hydroxyalkylgroup, respectively, which are recited as a substituent optionallycontained in the —SO₂-containing cyclic group.

Below, specific cyclic groups represented by the above formulae (3-1) to(3-4) will be illustrated. Note that “Ac” in the formulae represents anacetyl group.

As the —SO₂-containing cyclic group, among those shown above, a grouprepresented by the above formula (3-1) is preferred, and at least oneselected from the group consisting of the groups represented by any ofthe aforementioned formulae (3-1-1), (3-1-18), (3-3-1) and (3-4-1) ismore preferred, and a group represented by the aforementioned formula(3-1-1) is most preferred.

The “lactone-containing cyclic group” refers to a cyclic groupcontaining a ring (lactone ring) comprising —O—C(═O)— in the ringbackbone thereof. Considering the lactone ring as the first ring, agroup having that lactone ring alone is called a monocyclic group, and agroup further having another ring structure is called a polycyclic groupregardless of its structure. The lactone-containing cyclic group may bea monocyclic group, or may be a polycyclic group.

There is no particular limitation on the lactone cyclic group in theconstituent unit (b-3), and any can be used. Specifically,lactone-containing monocyclic groups include a group in which onehydrogen atom is removed from 4 to 6 membered ring lactone, a group inwhich one hydrogen atom is removed from, for example, β-propionolactone, a group in which one hydrogen atom is removed from,γ-butyrolactone, a group in which one hydrogen atom is removed fromδ-valerolactone and the like. Further, lactone-containing polycyclicgroups include a group in which one hydrogen atom is removed frombicycloalkane, tricycloalkane and tetracycloalkane having a lactonering.

There is no particular limitation on the structures in other part in theconstituent unit (b-3) as long as it has an —SO₂-containing cyclic groupor a lactone-containing cyclic group. However, preferred is at least oneconstituent unit selected from the group consisting of a constituentunit (b-3-S) derived from an acrylic acid ester comprising an—SO₂-containing cyclic group in which the hydrogen atom attached to thecarbon atom in the a position is optionally substituted with asubstituent; and a constituent unit (b-3-L) derived from an acrylic acidester comprising a lactone-containing cyclic group in which the hydrogenatom attached to the carbon atom in the a position is optionallysubstituted with a substituent.

Constituent Unit (b-3a-S)

More specifically, examples of the constituent unit (b-3a-S) include onerepresented by the following formula (b-S1).

(In the formula, R represents a hydrogen atom, an alkyl group having 1to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbonatoms; and R^(11b) represents an —SO₂-containing cyclic group; andR^(12b) represents a single-bond or divalent linking group.)

In the formula (b-S1), R is similarly defined as above. R^(11b) issimilarly defined as in the —SO₂-containing cyclic group describedabove. R^(12b) may be either a single-bond linking group or a divalentlinking group. A divalent linking group is preferred due to the superioreffect of the present invention.

There is no particular limitation on the divalent linking group inR^(12b), but suitable groups include a divalent hydrocarbon groupoptionally having a substituent, a divalent linking group comprising ahetero atom and the like.

For R^(12b), the hydrocarbon group as a divalent linking group may be analiphatic hydrocarbon group, or may be an aromatic hydrocarbon group.The aliphatic hydrocarbon group means a hydrocarbon group withoutaromaticity. The above aliphatic hydrocarbon group may be saturated ormay be unsaturated. Usually, a saturated hydrocarbon group is preferred.More specifically, examples of the above aliphatic hydrocarbon groupinclude a linear or branched aliphatic hydrocarbon group, an aliphatichydrocarbon group comprising a ring in the structure thereof and thelike.

The number of carbon atoms in the linear or branched aliphatichydrocarbon group is preferably 1 to 10, more preferably 1 to 8, andeven more preferably 1 to 5.

As the linear aliphatic hydrocarbon group, a linear alkylene group ispreferred. Specific examples include a methylene group [—CH₂—], anethylene group [—(CH₂)₂—], a trimethylene group [—(CH₂)₃—], atetramethylene group [—(CH₂)₄—], a pentamethylene group [—(CH₂)₅—] andthe like.

As the branched aliphatic hydrocarbon group, a branched alkylene groupis preferred. Specific examples include alkyl alkylene groups such asalkyl methylene groups such as —CH(CH₃)—, —CH(CH₂CH₃)—, —C(CH₃)₂—,—C(CH₃)(CH₂CH₃)—, —C(CH₃)(CH₂CH₂CH₃)— and —C(CH₂CH₃)₂—; alkyl ethylenegroups such as —CH(CH₃) CH₂—, —CH(CH₃) CH(CH₃)—, —C(CH₃)₂CH₂—,—CH(CH₂CH₃) CH₂— and —C(CH₂CH₃)₂—CH₂—; alkyl trimethylene groups such as—CH(CH₃) CH₂CH₂— and —CH₂CH(CH₃) CH₂—; alkyl tetramethylene groups suchas —CH(CH₃)CH₂CH₂CH₂— and —CH₂CH(CH₃)CH₂CH₂—; and the like. As an alkylgroup in the alkyl alkylene group, a linear alkyl group having 1 to 5carbon atoms is preferred.

The above linear or branched aliphatic hydrocarbon group may or may nothave a substituent (a group or atom other than a hydrogen atom) whichsubstitutes a hydrogen atom. Examples of the substituent include afluorine atom, a fluorinated alkyl group having 1 to 5 carbon atomssubstituted with a fluorine atom, an oxo group (═O) and the like.

Examples of the above aliphatic hydrocarbon group comprising a ring inthe structure thereof include a cyclic aliphatic hydrocarbon groupoptionally comprising a hetero atom in the structure (a group in whichtwo hydrogen atoms are removed from an aliphatic hydrocarbon ring); agroup in which the above cyclic aliphatic hydrocarbon group is attachedto an end of a linear or branched aliphatic hydrocarbon group; a groupin which the above cyclic aliphatic hydrocarbon group is present in alinear or branched aliphatic hydrocarbon group along the chain; and thelike. Examples of the above linear or branched aliphatic hydrocarbongroup include those similar to the above.

The number of carbon atoms in the cyclic aliphatic hydrocarbon group ispreferably 3 to 20, more preferably 3 to 12.

The cyclic aliphatic hydrocarbon group may be polycyclic, or may bemonocyclic. As the monocyclic aliphatic hydrocarbon group, a group inwhich two hydrogen atoms are removed from monocycloalkane is preferred.The number of carbon atoms in the above monocycloalkane is preferably 3to 6. Specific examples include cyclopentane, cyclohexane and the like.As the polycyclic aliphatic hydrocarbon group, a group in which twohydrogen atoms are removed from polycycloalkane is preferred. The numberof carbon atoms in the above polycycloalkane is preferably 7 to 12.Specific examples include adamantane, norbornane, isobornane,tricyclodecane, tetracyclododecane and the like.

The cyclic aliphatic hydrocarbon group may or may not have a substituentwhich substitutes a hydrogen atom (a group or atom other than a hydrogenatom). Examples of the above substituent include an alkyl group, analkoxy group, a halogen atom, a halogenated alkyl group, a hydroxygroup, an oxo group (═O) and the like.

For an alkyl group as the above substituent, an alkyl group having 1 to5 carbon atoms is preferred, and a methyl group, an ethyl group, apropyl group, an n-butyl group and a tert-butyl group are morepreferred.

For an alkoxy group as the above substituent, an alkoxy group having 1to 5 carbon atoms is preferred, and a methoxy group, an ethoxy group, ann-propoxy group, an iso-propoxy group, an n-butoxy group and atert-butoxy group are more preferred, and a methoxy group and an ethoxygroup are particularly preferred.

Halogen atoms as the above substituent include a fluorine atom, achlorine atom, a bromine atom, an iodine atoms and the like, and afluorine atom is preferred.

Halogenated alkyl groups as the above substituent include a group inwhich a part or all of hydrogen atoms in the aforementioned alkyl groupis(are) substituted with the above halogen atom(s).

In the cyclic aliphatic hydrocarbon group, a part of carbon atomsconstituting the ring structure thereof may be substituted with —O— or—S—. As the substituent comprising the above hetero atom, preferred are—O—, —C(═O)—O—, —S—, —S(═O)₂— and —S(═O)₂—O—.

The aromatic hydrocarbon group as the divalent hydrocarbon group is adivalent hydrocarbon group having at least one aromatic ring, and mayhave a substituent. There is no particular limitation on the aromaticring as long as it is an cyclic conjugated system having a 4n+2 πelectrons, and it may be monocyclic or may be polycyclic. The number ofcarbon atoms in the aromatic ring is preferably 5 to 30, more preferably5 to 20, even more preferably 6 to 15, and in particular preferably 6 to12, provided that the number of carbon atoms in a substituent shall notbe included in the above number of carbon atoms.

Specifically, aromatic rings include aromatic hydrocarbon rings such asbenzene, naphthalene, anthracene and phenanthrene; aromatic heterocyclesin which a part of the carbon atoms constituting the above aromatichydrocarbon ring is(are) substituted with hetero atom(s). Hetero atomsin the aromatic heterocycle include an oxygen atom, a sulfur atom, anitrogen atom and the like. Specifically, aromatic heterocycles includea pyridine ring, a thiophene ring and the like.

Specific examples of the aromatic hydrocarbon group as a divalenthydrocarbon group include a group in which two hydrogen atoms areremoved from the above aromatic hydrocarbon ring or the above aromaticheterocycle (an arylene group or a heteroarylene group); a group inwhich two hydrogen atoms are removed from an aromatic compoundcomprising two or more aromatic rings (for example, biphenyl, fluoreneand the like); a group in which one hydrogen atom from a group where onehydrogen atom is removed from the above aromatic hydrocarbon ring or theabove aromatic heterocycle (an aryl group or a heteroaryl group) issubstituted with an alkylene group (for example, a group in which onehydrogen atom is further removed from an aryl group in an arylalkylgroup such as a benzyl group, a phenethyl group, a 1-naphthylmethylgroup, a 2-naphthylmethyl group, a 1-naphthylethyl group and a2-naphthylethyl group); and the like.

The number of carbon atoms in the above alkylene group attached to anaryl group or a heteroaryl group is preferably 1 to 4, more preferably 1to 2, and in particular preferably 1.

In the above aromatic hydrocarbon group, a hydrogen atom of the abovearomatic hydrocarbon group may be substituted with a substituent. Forexample, a hydrogen atom attached to an aromatic ring in the abovearomatic hydrocarbon group may be substituted with a substituent.Examples of the substituent include an alkyl group, an alkoxy group, ahalogen atom, a halogenated alkyl group, a hydroxy group, an oxo group(═O) and the like.

For an alkyl group as the above substituent, an alkyl group having 1 to5 carbon atoms is preferred, and a methyl group, an ethyl group, ann-propyl group, an n-butyl group and a tert-butyl group are morepreferred.

For an alkoxy group as the above substituent, an alkoxy group having 1to 5 carbon atoms is preferred, and a methoxy group, an ethoxy group, ann-propoxy group, an iso-propoxy group, an n-butoxy group and atert-butoxy group are preferred, and a methoxy group and an ethoxy groupare more preferred.

Halogen atoms as the above substituent include a fluorine atom, achlorine atom, a bromine atom, an iodine atom and the like, and afluorine atom is preferred.

Halogenated alkyl groups as the above substituent include a group inwhich a part or all of hydrogen atoms in the aforementioned alkyl groupis(are) substituted with the above halogen atom(s).

For R^(12b), a hetero atom in the divalent linking group comprising ahetero atom is an atom other than a carbon atom and a hydrogen atom,including, for example, an oxygen atom, a nitrogen atom, a sulfur atom,a halogen atom and the like.

Specific examples of the divalent linking group comprising a hetero atominclude non-hydrocarbon based linking groups such as —O—, —C(═O)—,—C(═O)—O—, —O—C(═O)—O—, —S—, —S(═O)₂—, —S(═O)₂—O—, —NH—, —NH—C(═O)—,—NH—C(═NH)—, ═N—, and combinations of at least one of thesenon-hydrocarbon based linking groups and a divalent hydrocarbon groupand the like. Examples of the above divalent hydrocarbon group includethose similar to the aforementioned divalent hydrocarbon groupsoptionally having a substituent, and linear or branched aliphatichydrocarbon groups are preferred.

Among those described above, —NH— in —C(═O)—NH—, and H in —NH— and—NH—C(═NH)— may be substituted with a substituent such as an alkyl groupor an acyl group, respectively. The number of carbon atoms in the abovesubstituent is preferably 1 to 10, more preferably 1 to 8, and inparticular preferably 1 to 5.

As a divalent linking group in R^(12b), a linear or branched alkylenegroup, an cyclic aliphatic hydrocarbon group or a divalent linking groupcomprising a hetero atom is particularly preferred.

In a case where the divalent linking group in R^(12b) is a linear orbranched alkylene group, the number of carbon atoms in the abovealkylene group is preferably 1 to 10, more preferably 1 to 6, inparticular preferably 1 to 4, and most preferably 1 to 3. Specificexamples include those similar to the linear alkylene groups or branchedalkylene groups recited as a linear or branched aliphatic hydrocarbongroup in the description of the “divalent hydrocarbon group optionallyhaving a substituent” as the aforementioned divalent linking group.

In a case where the divalent linking group in R^(12b) is an cyclicaliphatic hydrocarbon group, examples of the above cyclic aliphatichydrocarbon group include those similar to the cyclic aliphatichydrocarbon groups recited as the “aliphatic hydrocarbon groupcomprising a ring in the structure” in the description of the “divalenthydrocarbon group optionally having a substituent” as the aforementioneddivalent linking group.

As the above cyclic aliphatic hydrocarbon group, particularly preferredis a group in which two or more hydrogen atoms are removed fromcyclopentane, cyclohexane, norbornane, isobornane, adamantane,tricyclodecane or tetracyclododecane.

In a case where the divalent linking group in R^(12b) is a divalentlinking group comprising a hetero atom, those preferred as the abovelinking groups include —O—, —C(═O)—O—, —C(═O)—, —O—C(═O)—O—, —C(═O)—NH—,—NH— (H may be substituted with a substituent such as an alkyl group oran acyl group), —S—, —S(═O)₂—, —S(═O)₂—O— and a group represented by theformula —Y¹—O—Y²—, —[Y¹—C(═)—O]_(m′)—Y²— or —Y¹—O—C(═O)—Y₂— (wherein Y¹and Y² are divalent hydrocarbon groups each independently, optionallyhaving a substituent, and O represents an oxygen atom, and m′ is aninteger of 0 to 3).

In a case where the divalent linking group in R^(12b) is —NH—, thehydrogen atom in —NH— may be substituted with a substituent such as analkyl group or an acyl group. The number of carbon atoms in the abovesubstituent (an alkyl group, an acyl group and the like) is preferably 1to 10, more preferably 1 to 8, and in particular preferably 1 to 5.

Y¹ and Y² in the formula Y¹—O—Y²—, —[Y¹—C(═O)—O]_(m′)—Y²— or—Y¹—O—C(═O)—Y²— are divalent hydrocarbon groups each independently,optionally having a substituent. Examples of the above divalenthydrocarbon group include those similar to the “divalent hydrocarbongroup optionally having a substituent” recited in the description of theabove divalent linking group.

As Y¹, a linear aliphatic hydrocarbon group is preferred, and a linearalkylene group is more preferred, and a linear alkylene group having 1to 5 carbon atoms is more preferred, and a methylene group and anethylene group are particularly preferred.

As Y², a linear or branched aliphatic hydrocarbon group is preferred,and a methylene group, an ethylene group and an alkylmethylene group aremore preferred. The alkyl group in the above alkylmethylene group ispreferably a linear alkyl group having 1 to 5 carbon atoms, morepreferably a linear alkyl group having 1 to 3 carbon atoms, and inparticular preferably a methyl group.

In a group represented by the formula —[Y¹—C(═O)—O]_(m′)—Y²—, m′ is aninteger of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or1, and in particular preferably 1. That is, as a group represented bythe formula —[Y¹—C(═O)—O]_(m′)—Y²—, a group represented by the formula—Y¹—C(═O)—O—Y²— is particularly preferred. Among these, a grouprepresented by the formula —(CH₂)_(a′)—C(═O)—O—(CH₂)_(b′)— is preferred.In the above formula, a′ is an integer of 1 to 10, preferably an integerof 1 to 8, more preferably an integer of 1 to 5, even more preferably 1or 2, and most preferably 1.

b′ is an integer of 1 to 10, preferably an integer of 1 to 8, morepreferably an integer of 1 to 5, even more preferably 1 or 2, and mostpreferably 1.

With regard to the divalent linking group in R^(12b), an organic groupcomprising a combination of at least one non-hydrocarbon group and adivalent hydrocarbon group is preferred as the divalent linking groupcomprising a hetero atom. Among these, a linear chain group having anoxygen atom as a hetero atom, for example, a group comprising an etherbond or an ester bond is preferred, and a group represented by theformula —Y¹—O—Y²—, —[Y¹—C(═O)—O]_(m′)—Y²— or —Y¹—O—C(═O)—Y²— is morepreferred, and a group represented by the above formula—[Y¹⁻C(O)—O]_(m′)—Y²— or —Y¹—O—C(═O)—Y²— is particularly preferred.

As the divalent linking group in R^(12b), one comprising an alkylenegroup or an ester bond (—C(═O)—O—) is preferred.

The above alkylene group is preferably a linear or branched alkylenegroup. Suitable examples of the above linear aliphatic hydrocarbon groupinclude a methylene group [—CH₂—], an ethylene group [—(CH₂)₂—], atrimethylene group [—(CH₂)₃—], a tetramethylene group [—(CH₂)₄—], apentamethylene group [—(CH₂)₅—] and the like. Suitable examples of theabove branched alkylene group include alkyl alkylene groups such asalkyl methylene groups such as —CH(CH₃)—, —CH(CH₂CH₃)—, —C(CH₃)₂—,—C(CH₃)(CH₂CH₃)—, —C(CH₃)(CH₂CH₂CH₃)— and —C(CH₂CH₃)₂—; alkyl ethylenegroups such as —CH(CH₃)CH₂—, —CH(CH₃)CH(CH₃)—, —C(CH₃)₂CH₂—,—CH(CH₂CH₃)CH₂— and —C(CH₂CH₃)₂—CH₂—; alkyl trimethylene groups such as—CH(CH₃) CH₂CH₂— and —CH₂CH(CH₃) CH₂—; alkyl tetramethylene groups suchas —CH(CH₃)CH₂CH₂CH₂— and —CH₂CH(CH₃) CH₂CH₂—.

As the divalent linking group comprising an ester bond, particularlypreferred is a group represented by the formula: —R^(13b)—C(═O)—O—[wherein R^(13b) represents a divalent linking group.]. That is, theconstituent unit (b-3a-S) is preferably one represented by the followingformula (b-S1-1).

(In the formula, R and R^(11b) are each similar to the above, and Rnbrepresents a divalent linking group.)

There is no particular limitation for R^(12b), including, for example,those similar to the aforementioned divalent linking group in R^(12b).As the divalent linking group in R^(13b), a linear or branched alkylenegroup, an aliphatic hydrocarbon group comprising a ring in thestructure, or a divalent linking group comprising a hetero atom ispreferred, and a linear or branched alkylene group or a divalent linkinggroup comprising an oxygen atom as a hetero atom is preferred.

As the linear alkylene group, a methylene group or an ethylene group ispreferred, and a methylene group is particularly preferred. As thebranched alkylene group, an alkylmethylene group or an alkylethylenegroup is preferred, and —CH(CH₃)—, —C(CH₃)₂— or —C(CH₃)₂CH₂— isparticularly preferred.

As the divalent linking group comprising an oxygen atom, a divalentlinking group comprising an ether bond or an ester bond is preferred,and the aforementioned —Y₁—O—Y²—, —[Y¹—C(═O)—O]_(m′)—Y²— or—Y¹—O—C(═O)—Y²— is more preferred. Y¹ and Y² are each independentlydivalent hydrocarbon groups optionally having a substituent, and m′ isan integer of 0 to 3. Among these, —Y¹—O—C(═O)—Y²— is preferred, and agroup represented by —(CH₂)_(c)—O—C(═O)—(CH₂)_(d)— is particularlypreferred. c is an integer of 1 to 5, and 1 or 2 is preferred. d is aninteger of 1 to 5, and 1 or 2 is preferred.

As the constituent unit (b-3a-S), in particular, one represented by thefollowing formula (b-S1-11) or (b-S1-12) is preferred, and onerepresented by the formula (b-S1-12) is more preferred.

(In the formulae, R, A′, R^(10b), z and R^(13b) are each the same as theabove.)

In the formula (b-S1-11), A′ is preferably a methylene group, an oxygenatom (—O—) or a sulfur atom (—S—).

As R^(13b), preferred is a linear or branched alkylene group or adivalent linking group comprising an oxygen atom. Examples of the linearor branched alkylene group and the divalent linking group comprising anoxygen atom in R^(13b) include those similar to the aforementionedlinear or branched alkylene group and the aforementioned divalentlinking group comprising an oxygen atom, respectively.

As the constituent unit represented by the formula (b-S1-12),particularly preferred is one represented by the following formula(b-S1-12a) or (b-S1-12b).

(In the formulae, R and A′ are each the same as the above, and c to eare each independently an integer of 1 to 3.)Constituent Unit (b-3a-L)

Examples of the constituent unit (b-3a-L) include, for example, those inwhich R^(11b) in the aforementioned formula (b-S1) is substituted with alactone-containing cyclic group, and more specifically include thoserepresented by the following formulae (b-L1) to (b-L5).

(In the formulae, R represents a hydrogen atom, an alkyl group having 1to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbonatoms; R′ represents each independently a hydrogen atom, an alkyl group,an alkoxy group, a halogenated alkyl group, a hydroxy group, —COOR″,—OC(═O)R″, a hydroxyalkyl group or a cyano group, and R″ represents ahydrogen atom or an alkyl group; R^(12b) represents a single bond ordivalent linking group, and s″ is an integer of 0 to 2; A″ represents analkylene group having 1 to 5 carbon atoms optionally comprising anoxygen atom or a sulfur atom, an oxygen atom or a sulfur atom; and r is0 or 1.)

R in the formulae (b-L1) to (b-L5) is the same as the above. Examples ofthe alkyl group, the alkoxy group, the halogenated alkyl group, —COOR″,—OC(═O)R″ and the hydroxyalkyl group in R′ include those similar to thealkyl group, the alkoxy group, the halogenated alkyl group, —COOR″,—OC(═O)R″ and the hydroxyalkyl group recited as a substituent optionallycontained in the —SO₂-containing cyclic group, respectively.

R′ is preferably a hydrogen atom in view of easy industrialavailability. The alkyl group in R″ may be any of a linear, branched orcyclic chain. In a case where R″ is a linear or branched alkyl group,the number of carbon atoms is preferably 1 to 10, more preferably 1 to5. In a case where R″ is a cyclic alkyl group, the number of carbonatoms is preferably 3 to 15, more preferably 4 to 12, and mostpreferably 5 to 10. Specific examples include a group in which one ormore hydrogen atoms are removed from monocycloalkane and polycycloalkanesuch as tricycloalkane and tetracycloalkane and the like optionallysubstituted with a fluorine atom or a fluorinated alkyl group. Specificexamples include a group in which one or more hydrogen atoms are removedfrom monocycloalkane such as cyclopentane and cyclohexane; andpolycycloalkane such as adamantane, norbornane, isobornane,tricyclodecane and tetracyclododecane; and the like. Examples of A″include those similar to A′ in the aforementioned formula (3-1). A″ ispreferably an alkylene group having 1 to 5 carbon atoms, an oxygen atom(—O—) or a sulfur atom (—S—), more preferably an alkylene group having 1to 5 carbon atoms or —O—. As the alkylene group having 1 to 5 carbonatoms, a methylene group or a dimethylmethylene group is more preferred,and a methylene group is most preferred.

R^(12b) is similar to R^(12b) in the aforementioned formula (b-S1). Inthe formula (b-L1), s″ is preferably 1 to 2. Below, specific examples ofthe constituent units represented by the aforementioned formulae (b-L1)to (b-L3) will be illustrated. In each of the following formulae, R^(α)represents a hydrogen atom, a methyl group or a trifluoromethyl group.

As the constituent unit (b-3a-L), at least one selected from the groupconsisting of the constituent units represented by the aforementionedformulae (b-L1) to (b-L5) is preferred, and at least one selected fromthe group consisting of the constituent units represented by theformulae (b-L1) to (b-L3) is more preferred, and at least one selectedfrom the group consisting of the constituent units represented by theaforementioned formula (b-L1) or (b-L3) is particularly preferred. Amongthese, at least one selected from the group consisting of theconstituent units represented by the aforementioned formulae (b-L1-1),(b-L1-2), (b-L2-1), (b-L2-7), (b-L2-12), (b-L2-14), (b-L3-1) and(b-L3-5) is preferred.

Further, as the constituent unit (b-3-L), the constituent unitsrepresented by following formulae (b-L6) to (b-L7) are also preferred.

R and R^(12b) in the formulae (b-L6) and (b-L7) are the same as theabove.

(Constituent Unit (b-3b))

The constituent unit (b-3b) comprising an organic group comprising anaromatic group and an alcoholic hydroxyl group will be described. Apattern having a favorable sectional shape is likely to be formed whenthe photosensitive resin composition incorporates an (B-3) acrylic resincomprising a combination of the constituent unit (b-3a) and theconstituent unit (b-3b).

As long as the constituent unit (b-3b) comprises an organic groupcomprising an aromatic group and an alcoholic hydroxyl group, thestructure of other moieties is not particularly limited. Preferably, theconstituent unit (b-3b) is preferably a constituent unit (b-3b-H)derived from an acrylic acid ester containing an organic groupcomprising an aromatic group and an alcoholic hydroxyl group and whereina hydrogen atom bonded to the carbon atom at the a position may besubstituted by a substituent. The constituent unit (b-3b-H) will bedescribed later.

In the constituent unit (b-3b), the aromatic group may be an aromatichydrocarbon group or an aromatic heterocyclic group and is preferably anaromatic hydrocarbon group.

The aromatic group may be of any type without particular limitation aslong as the object of the present invention is not impaired. The organicgroup may be a monovalent group or a divalent or higher group. Thearomatic group is preferably a monovalent or divalent aromatic group.The number of aromatic groups in the constituent unit (b-3b) is notparticularly limited and may be 1 or 2 or more, preferably 1.

The aromatic hydrocarbon group may be a monocyclic aromatic group, agroup formed by condensing two or more aromatic hydrocarbon groups, or agroup formed by bonding two or more aromatic hydrocarbon groups througha single bond. The aromatic hydrocarbon group is a group obtained byremoving the same number of hydrogen atoms as the valence of thearomatic hydrocarbon group from various aromatic hydrocarbon groups.Preferred aromatic hydrocarbons which provide preferred aromatichydrocarbon groups include benzene, naphthalene, biphenyl, anthracene,and phenanthrene.

The aromatic heterocyclic group may be of any type without particularlimitation as long as the object of the present invention is notimpaired. The aromatic heterocyclic group may be a monocyclic group or apolycyclic group. Examples of aromatic heterocyclic rings that providepreferred aromatic heterocyclic groups include pyridine, furan,thiophene, imidazole, pyrazole, oxazole, thiazole, isoxazole,isothiazole, benzoxazole, benzothiazole, and benzimidazole.

The aromatic groups described above may be substituted as long as theobject of the present invention is not impaired. Examples of preferredsubstituents include a halogen atom, a silyl group, a nitro group, anitroso group, an alkyl group (preferably an alkyl group having 1 to 6carbon atoms), an alkoxy group (preferably an alkoxy group having 1 to 6carbon atoms, an alkylthio group (preferably an alkylthio group having 1to 6 carbon atoms), an aliphatic acyl group (preferably an aliphaticacyl group having 2 to 6 carbon atoms), and a cyano group. When thearomatic group is substituted, the number of substituents is notparticularly limited, and is preferably 1 to 5, more preferably 1 to 3,for example. The aromatic group is preferably unsubstituted.

The organic group having an alcoholic hydroxyl group is not particularlylimited as long as the organic group is a group comprising an aliphatichydrocarbon group containing an alcoholic hydroxyl group. In the organicgroup containing an alcoholic hydroxyl group, the alcoholic hydroxylgroup may be a primary hydroxyl group, a secondary hydroxyl group, or atertiary hydroxyl group.

The organic group containing an alcoholic hydroxyl group may contain abond containing a hetero atom, for example, an ether bond (—O—), acarbonyl group (—CO—), an ester bond (—CO—O—), a carbonate bond(—CO—O—CO—), an amino group (—NH—), an amide bond (—CO—NH—), a urethanebond (—NH—CO—NH—), a sulfide bond (—S—), a disulfide bond (—S—S—), andthe like. However, the organic group containing an alcoholic hydroxylgroup does not contain a lactone ring or an —SO₂-containing ring.

The organic group containing an alcoholic hydroxyl group may be amonovalent group or a divalent or higher group. The organic groupcontaining an alcoholic hydroxyl group is preferably a monovalent ordivalent group.

The aromatic group and the organic group containing an alcoholichydroxyl group may be bonded to each other or may not be bonded to eachother, and are preferably bonded to each other. Preferred groupsobtained by bonding the aromatic group and the alcoholic hydroxyl groupinclude groups represented by the following formulae (i) to (Viii).

—R^(14b)(OH)—O—R^(15b)  (i)

—R^(14b)(OH)—CO—O—R^(15b)  (ii)

—R^(14b)(OH)—O—CO—R^(15b)  (iii)

—R^(14b)(OH)—R^(15b)  (iv)

—R^(16b)—O—R^(17b)—OH  (v)

—R^(16b)—CO—O—R^(17b)—OH  (vi)

—R^(16b)—O—CO—R^(17b)—OH  (vii)

—R^(16b)—R^(17b)—OH  (viii)

In the formulae (i) to (viii), R^(14b) is a trivalent aliphatichydrocarbon group, R^(15b) is a monovalent aromatic group, R^(16b) is adivalent aromatic group, and R^(17b) is a divalent aliphatic hydrocarbongroup. For R^(14b) and R^(15b), the aliphatic hydrocarbon group may beof either linear or branched type and is preferably linear. The numberof carbon atoms in the aliphatic hydrocarbon group is preferably 2 to20, more preferably 2 to 10, particularly preferably 2 to 6. For R^(15b)and R^(16b), preferred aromatic groups are as follows. Specifically, forR^(15b), monovalent aromatic groups obtained by removing one hydrogenatom from benzene, naphthalene, biphenyl, anthracene, phenanthrene,pyridine, furan, thiophene, imidazole, pyrazole, oxazole, thiazole,isoxazole, isothiazole, benzoxazole, benzothiazole, or benzimidazole arepreferred, and, for R^(16b), divalent aromatic groups obtained byremoving two hydrogen atoms from these aromatic compounds are preferred.

Constituent Unit (b-3b-H)

More specifically, examples of constituent units (b-3b-H) include thoserepresented by the following formula (b-H1).

(In the formula (b-H1), R represents a hydrogen atom, an alkyl grouphaving 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5carbon atoms; R^(18b) represents a linear or branched aliphatichydrocarbon group having 2 to 20 carbon atoms; and R^(19b) represents anaromatic hydrocarbon group.)

For R^(18b), the number of carbon atoms in the aliphatic hydrocarbongroup is preferably 2 to 10, more preferably 2 to 6. Phenyl, α-naphthyl,β-naphthyl, 4-phenylphenyl, 3-phenylphenyl, and 2-phenylphenyl groupsare preferred as R^(19b).

Preferred specific examples of the constituent unit represented by theformula (b-H1) include constituent units represented by the followingformulas (b-H1-1) to (b-H1-24).

(Other Constituent Units)

Further, the (B-3) acrylic resin contains an acid-dissociabledissolution-inhibiting group and comprises constituent units representedby the following formulae (b5) to (b7) as constituent units that enhancethe solubility of the (B-3) acrylic resin in alkali under the action ofacid.

In the formulae (b5) to (b7), R^(20b) and R^(24b) to R^(29b) eachindependently represent a hydrogen atom, a linear or branched alkylgroup having 1 to 6 carbon atoms, a fluorine atom, or a linear orbranched fluorinated alkyl group having 1 to 6 carbon atoms; R^(21b) toR^(23b) each independently represent a linear or branched alkyl grouphaving 1 to 6 carbon atoms, a linear or branched fluorinated alkyl grouphaving 1 to 6 carbon atoms, or an aliphatic cyclic group having 5 to 20carbon atoms; and R^(22b) and R^(23b) may be bonded to each other toform a hydrocarbon ring having 5 to 20 carbon atoms together with thecarbon atom to which both the groups are bonded; Y^(b) represents anoptionally substituted aliphatic group or alkyl group; p is an integerof 0 to 4; and q is 0 or 1.

Examples of the linear or branched alkyl group include a methyl group,ethyl group, propyl group, isopropyl group, n-butyl group, isobutylgroup, tert-butyl group, pentyl group, isopentyl group, neopentyl group,and the like. The fluorinated alkyl group refers to the abovementionedalkyl groups of which the hydrogen atoms are partially or entirelysubstituted with fluorine atoms. Specific examples of aliphatic cyclicgroups include groups obtained by removing one or more hydrogen atomsfrom monocycloalkanes or polycycloalkanes such as bicycloalkanes,tricycloalkanes, and tetracycloalkane. Specifically, groups obtained byremoving one hydrogen atom from a monocycloalkane such as cyclopentane,cyclohexane, cycloheptane, or cyclooctane, or a polycycloalkane such asadamantane, norbornane, isobornane, tricyclodecane, ortetracyclododecane may be mentioned. In particular, groups obtained byremoving one hydrogen atom from cyclohexane or adamantane (which mayfurther be substituted) are preferred.

When R^(22b) and R^(23b) do not combine with each other to form ahydrocarbon ring, R^(21b), RR^(22b), and R^(23b) preferably represent alinear or branched alkyl group having 2 to 4 carbon atoms, for example,from the viewpoints of a high contrast and favorable resolution anddepth of focus. R^(25b), R^(26b), R^(28b), and R^(29b) preferablyrepresent a hydrogen atom or a methyl group.

The above R^(22b) and R^(23b) may form an aliphatic cyclic group having5 to 20 carbon atoms together with a carbon atom to which the both areattached. Specific examples of the alicyclic group are the groups ofmonocycloalkanes and polycycloalkanes such as bicycloalkanes,tricycloalkanes and tetracycloalkanes from which at least one hydrogenatom is removed. Specific examples thereof are monocycloalkanes such ascyclopentane, cyclohexane, cycloheptane and cyclooctane andpolycycloalkanes such as adamantane, norbornane, isobornane,tricyclodecane and tetracyclododecane from which at least one hydrogenatom is removed. Particularly preferable are cyclohexane and adamantanefrom which at least one hydrogen atom is removed (that may further havea substituent).

Further, in a case where an aliphatic cyclic group to be formed with theabove R^(22b) and R^(23b) has a substituent on the ring backbonethereof, examples of the substituent include a polar group such as ahydroxy group, a carboxyl group, a cyano group and an oxygen atom (═O),and a linear or branched alkyl group having 1 to 4 carbon atoms. As thepolar group, an oxygen atom (═O) is particularly preferred.

The aforementioned Y^(b) is an alicyclic group or an alkyl group; andexamples thereof are monocycloalkanes and polycycloalkanes such asbicycloalkanes, tricycloalkanes and tetracycloalkanes from which atleast one hydrogen atom is removed. Specific examples thereof aremonocycloalkanes such as cyclopentane, cyclohexane, cycloheptane andcyclooctane, and polycycloalkanes such as adamantane, norbornane,isobornane, tricyclodecane and tetracyclododecane, from which at leastone hydrogen atom is removed. Particularly preferable is adamantane fromwhich at least one hydrogen atom is removed (that may further have asubstituent).

When the alicyclic group of the abovementioned Y^(b) has a substituenton the ring skeleton, the substituent is exemplified by polar groupssuch as a hydroxide group, carboxyl group, cyano group and oxygen atom(═O), and linear or branched lower alkyl groups having 1 to 4 carbonatoms. The polar group is preferably an oxygen atom (═O) in particular.

When Y^(b) is an alkyl group, it is preferably a linear or branchedalkyl group having 1 to 20 carbon atoms, and more preferably 6 to 15carbon atoms. Preferably, the alkyl group is an alkoxyalkyl group inparticular; and examples of the alkoxyalkyl group include a1-methoxyethyl group, 1-ethoxyethyl group, 1-n-propoxyethyl group,1-isopropoxyethyl group, 1-n-butoxyethyl group, 1-isobutoxyethyl group,1-tert-butoxyethyl group, 1-methoxypropyl group, 1-ethoxypropyl group,1-methoxy-1-methylethyl group, 1-ethoxy-1-methylethyl group, and thelike.

Preferable specific examples of the structural unit represented by theabove formula (b5) are those represented by the following formulae(b5-1) to (b5-33).

In the formulae (b5-1) to (b5-33), R^(30b) represents a hydrogen atom ora methyl group.

Preferable specific examples of the structural unit represented by theformula (b6) include those represented by the following formulae (b6-1)to (b6-26).

In the formulae (b6-1) to (b6-26), R^(30b) represents a hydrogen atom ora methyl group.

Preferable specific examples of the structural unit represented by theformula (b7) include those represented by the following formulae (b7-1)to (b7-15).

In the above formula (b7-1) to (b7-15), R^(30b) represents a hydrogenatom or a methyl group.

Among the constituent units represented by the formulae (b5) to (b7)described above, those represented by the formula (b6) are preferred inthat they can be easily synthesized and relatively easily sensitized.Further, among the constituent units represented by the formula (b6),those in which Y^(b) is an alkyl group are preferred, and those in whichone or both of R^(25b) and R^(26b) are alkyl groups are preferred.

Further, the (B-3) acrylic resin is preferably a resin comprising acopolymer comprising a constituent unit derived from a polymerizablecompound having an ether bond together with a constituent unitrepresented by the above formulae (b5) to (b7).

Illustrative examples of the polymerizable compound having an etherlinkage include radical polymerizable compounds such as (meth)acrylicacid derivatives having an ether linkage and an ester linkage, andspecific examples thereof include 2-methoxyethyl (meth)acrylate,2-ethoxyethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate,3-methoxybutyl (meth)acrylate, ethylcarbitol (meth)acrylate,phenoxypolyethylene glycol (meth)acrylate, methoxypolyethylene glycol(meth)acrylate, methoxypolypropylene glycol (meth)acrylate,tetrahydrofurfuryl (meth)acrylate, and the like. Also, the polymerizablecompound having an ether linkage is preferably, 2-methoxyethyl(meth)acrylate, 2-ethoxyethyl (meth)acrylate, or methoxytriethyleneglycol (meth)acrylate. These polymerizable compounds may be used alone,or in combinations of two or more thereof.

Furthermore, the (B-3) acrylic resin may contain another polymerizablecompound as a structural unit in order to moderately control physical orchemical properties. T he polymerizable compound is exemplified byconventional radical polymerizable compounds and anion polymerizablecompounds.

Examples of the polymerizable compound include monocarboxylic acids suchas acrylic acid, methacrylic acid and crotonic acid; dicarboxylic acidssuch as maleic acid, fumaric acid and itaconic acid; methacrylic acidderivatives having a carboxyl group and an ester bond such as2-methacryloyloxyethyl succinic acid, 2-methacryloyloxyethyl maleicacid, 2-methacryloyloxyethyl phthalic acid and 2-methacryloyloxyethylhexahydrophthalic acid; (meth)acrylic acid alkyl esters such asmethyl(meth)acrylate, ethyl(meth)acrylate, butyl(meth)acrylate andcyclohexyl(meth)acrylate; (meth)acrylic acid hydroxyalkyl esters such as2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate;(meth)acrylic acid aryl esters such as phenyl (meth)acrylate and benzyl(meth)acrylate; dicarboxylic acid diesters such as diethyl maleate anddibutyl fumarate; vinyl group-containing aromatic compounds such asstyrene, α-methylstyrene, chlorostyrene, chloromethylstyrene,vinyltoluene, hydroxystyrene, α-methylhydroxystyrene andα-ethylhydroxystyrene; vinyl group-containing aliphatic compounds suchas vinyl acetate; conjugated diolefins such as butadiene and isoprene;nitrile group-containing polymerizable compounds such as acrylonitrileand methacrylonitrile; chlorine-containing polymerizable compounds suchas vinyl chloride and vinylidene chloride; amide bond-containingpolymerizable compounds such as acrylamide and methacrylamide; and thelike.

As described above, the (B-3) acrylic resin may comprise a constituentunit derived from a polymerizable compound having a carboxyl group suchas the above monocarboxylic acids and dicarboxylic acids. However, it ispreferable that the (B-3) acrylic resin does not substantially contain aconstituent unit derived from a polymerizable compound containing acarboxyl group, since a resist pattern including a nonresist portionhaving a favorable footing-free rectangular sectional shape can easilybe formed. Specifically, the proportion of a constituent unit derivedfrom a polymerizable compound having a carboxyl group in the (B-3)acrylic resin is preferably 5% by mass or less, more preferably 3% bymass or less, and in particular preferably 1% by mass or less.

Furthermore, examples of the polymerizable compound include(meth)acrylic acid esters having a non-acid-dissociable aliphaticpolycyclic group, and vinyl group-containing aromatic compounds. As thenon-acid-dissociable aliphatic polycyclic group, particularly, atricyclodecanyl group, an adamantyl group, a tetracyclododecanyl group,an isobornyl group, a norbornyl group, and the like are preferred fromthe viewpoint of easy industrial availability. These aliphaticpolycyclic groups may have a linear or branched alkyl group having 1 to5 carbon atoms as a substituent.

Specific examples of the (meth)acrylic acid esters having anon-acid-dissociable aliphatic polycyclic group include compounds havingstructures represented by the following formulae (b8-1) to (b8-5).

In formulae (b8-1) to (b8-5), R^(31b) represents a hydrogen atom or amethyl group.

As the (B-3) acrylic resin, those comprising 5% by mass or more of theconstituent unit (b-3a) comprising a —SO₂-containing cyclic group or alactone-containing cyclic group are preferred, and those comprising 10%by mass or more are more preferred, and those comprising 10 to 50% bymass are particularly preferred, and those comprising 10 to 40% by massare most preferred. In a case where the photosensitive resin compositioncomprises the constituent unit (b-3) comprising an —SO₂-containingcyclic group or a lactone-containing cyclic group in an amount withinthe range described above, good developmentability and a good patternshape can be easily achieved simultaneously.

The (B-3) acrylic resin preferably contains 1% by mass or more, morepreferably 5% by mass or more, particularly preferably 5 to 50% by mass,most preferably 5 to 30% by mass, of a constituent unit (b-3b)comprising an organic group containing an aromatic group and analcoholic hydroxyl group. When the photosensitive resin compositioncontains the constituent unit (b-3b) comprising an organic groupcontaining an aromatic group and an alcoholic hydroxyl group in theabove-defined range, a pattern having a favorable shape can easily beformed.

Further, in the (B-3) acrylic resin, a constituent unit represented bythe aforementioned formulae (b5) to (b7) is preferably contained in anamount of 5% by mass or more, more preferably 10% by mass or more, andin particular preferably 10 to 50% by mass.

The (B-3) acrylic resin preferably comprises the above constituent unitderived from a polymerizable compound having an ether bond. The contentof the constituent unit derived from a polymerizable compound having anether bond in the (B-3) acrylic resin is preferably 0 to 50% by mass,more preferably 5 to 30% by mass.

The (B-3) acrylic resin preferably comprises the above constituent unitderived from (meth)acrylic acid esters having a non-acid-dissociablealiphatic polycyclic group. The content of the constituent unit derivedfrom (meth)acrylic acid esters having a non-acid-dissociable aliphaticpolycyclic group in the (B-3) acrylic resin is preferably 0 to 50% bymass, more preferably 5 to 30% by mass.

As long as the photosensitive resin composition contains a predeterminedamount of the (B-3) acrylic resin, an acrylic resin other than the (B-3)acrylic resin described above can also be used as the (B) resin. Thereis no particular limitation for such an acrylic resin other than the(B-3) acrylic resin as long as it comprises a constituent unitrepresented by the formulae (b5) to (b7).

The mass-average molecular weight of the (B) resin described above interms of polystyrene is preferably 10000 to 600000, more preferably20000 to 400000, and even more preferably 30000 to 300000. Amass-average molecular weight within these ranges allows aphotosensitive resin layer to maintain sufficient strength withoutreducing detachability from a substrate, and can further prevent aswelled profile and crack generation when plating.

It is also preferred that the (B) resin has a dispersivity of no lessthan 1.05. Dispersivity herein indicates a value of a mass averagemolecular weight divided by a number average molecular weight. Adispersivity in the range described above can avoid problems withrespect to stress resistance on intended plating or possible swelling ofmetal layers resulting from the plating process.

The content of the (B) resin is preferably 5 to 60% by mass with respectto the total mass of the photosensitive resin composition.

<(C) Alkali-Soluble Resin>

The photosensitive resin composition may further contain a (C)alkali-soluble resin in order to improve crack resistance, if necessary.The alkali-soluble resin as referred to herein may be determined asfollows. A solution of the resin to give a resin concentration of 20% bymass (solvent: propylene glycol monomethyl ether acetate) is used toform a resin film having a film thickness of 1 μm on a substrate, andimmersed in an aqueous 2.38% by mass TMAH solution for 1 min.

As the (C) alkali-soluble resin, various resins conventionallycompounded in a positive-type photosensitive resin composition may beused within a range where the objects of the present invention are notimpaired. However, the photosensitive resin composition preferably doesnot comprise a resin having a carboxyl group as an alkali-soluble group.As the (C) alkali-soluble resin, preferred is at least one resinselected from the group consisting of a (C1) novolak resin, a (C2)polyhydroxystyrene resin and a (C3) acrylic resin. [(C1) Novolak resin]

The (C1) novolak resin may be prepared by addition condensation between,for example, aromatic compounds having a phenolic hydroxy group(hereinafter, merely referred to as “phenols”) and aldehydes in thepresence of an acid catalyst.

Examples of the phenols include phenol, o-cresol, m-cresol, p-cresol,o-ethylphenol, m-ethylphenol, p-ethylphenol, o-butylphenol,m-butylphenol, p-butylphenol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol,2,6-xylenol, 3,4-xylenol, 3,5-xylenol, 2,3,5-trimethyl phenol,3,4,5-trimethyl phenol, p-phenylphenol, resorcinol, hydroquinone,hydroquinone monomethyl ether, pyrogallol, phloroglycinol,hydroxydiphenyl, bisphenol A, gallic acid, gallic acid ester,α-naphthol, β-naphthol, and the like. Examples of the aldehydes includeformaldehyde, furfural, benzaldehyde, nitrobenzaldehyde, acetaldehyde,and the like. The catalyst used in the addition condensation reaction,which is not specifically limited, is exemplified by hydrochloric acid,nitric acid, sulfuric acid, formic acid, oxalic acid, acetic acid, etc.,in regards to acid catalyst.

The flexibility of the novolak resins can be enhanced still more wheno-cresol is used, a hydrogen atom of a hydroxide group in the resins issubstituted with other substituents, or bulky aldehydes are used.

The mass average molecular weight [sic] of (C1) novolac resin is notparticularly limited as long as the purpose of the present invention isnot impaired, but the mass average molecular weight is preferably 1,000to 50,000.

[(C2) Polyhydroxystyrene Resin]

The hydroxystyrene compound to constitute the (C2) polyhydroxystyreneresin is exemplified by p-hydroxystyrene, α-methylhydroxystyrene,α-ethylhydroxystyrene, and the like.

Among these, the (C2) polyhydroxystyrene resin is preferably prepared togive a copolymer with a styrene resin. The styrene compound toconstitute the styrene resin is exemplified by styrene, chlorostyrene,chloromethylstyrene, vinyltoluene, α-methylstyrene, and the like.

The mass average molecular weight of the (C2) polyhydroxystyrene resinis not particularly limited as long as the purpose of the presentinvention is not impaired, but the mass average molecular weight ispreferably 1,000 to 50,000.

[(C3) Acrylic Resin]

It is preferred that the (C3) acrylic resin includes a structural unitderived from a polymerizable compound having an ether linkage and astructural unit derived from a polymerizable compound having a carboxylgroup.

Illustrative examples of the polymerizable compound having an etherlinkage include (meth)acrylic acid derivatives having an ether linkageand an ester linkage such as 2-methoxyethyl (meth)acrylate,methoxytriethylene glycol (meth)acrylate, 3-methoxybutyl (meth)acrylate,ethylcarbitol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate,methoxypolypropylene glycol (meth)acrylate, tetrahydrofurfuryl(meth)acrylate, and the like. The polymerizable compound having an etherlinkage is preferably, 2-methoxyethyl acrylate, and methoxytriethyleneglycol acrylate. These polymerizable compounds may be used alone, or incombinations of two or more.

Illustrative examples of the polymerizable compound having a carboxylgroup include monocarboxylic acids such as acrylic acid, methacrylicacid and crotonic acid; dicarboxylic acids such as maleic acid, fumaricacid and itaconic acid; compounds having a carboxyl group and an esterlinkage such as 2-methacryloyloxyethyl succinic acid,2-methacryloyloxyethyl maleic acid, 2-methacryloyloxyethyl phthalic acidand 2-methacryloyloxyethyl hexahydrophthalic acid. The polymerizablecompound having a carboxyl group is preferably, acrylic acid andmethacrylic acid. These polymerizable compounds may be used alone, or incombinations of two or more thereof.

The mass average molecular weight of the (C3) acrylic resin is notparticularly limited as long as the purpose of the present invention isnot impaired, but the mass average molecular weight is preferably 50,000to 800,000.

The (C) alkali-soluble resin is used such that the content of the (B-3)acrylic resin containing a constituent unit derived from an acrylic acidester comprising the aforementioned —SO₂-containing cyclic group or thelactone-containing cyclic group relative to the total mass of the (B)resin and the (C) alkali-soluble resin in a photosensitive resincomposition is 70% by mass or more. Therefore, the content of the (C)alkali soluble resin in a photosensitive resin composition is 30% bymass or less relative to the total amount of the above (B) resin resinand the (C) alkali soluble resin, preferably 20% by mass or less, morepreferably 10% by mass or less, and in particular preferably 0% by mass.A low content of the (C) alkali soluble resin tends to produce aphotosensitive resin composition having superior sensitivity.

<D) Acid-Diffusion Control Agent>

Preferably, a photosensitive resin composition further contains a (D)acid-diffusion control agent in order to improve the formation of a goodpattern shape and the post-exposure delay stability of a photosensitiveresin film. As the (D) acid-diffusion control agent, a (D1)nitrogen-containing compound is preferred, and if desired, a (D2)organic carboxylic acid, or an oxo acid of phosphorus or derivativesthereof may be further contained.

[(D1) Nitrogen-Containing Compound]

Examples of the (D1) nitrogen-containing compound (E1) includetrimethylamine, diethylamine, triethylamine, di-n-propylamine,tri-n-propylamine, tri-n-pentylamine, tribenzylamine, diethanolamine,triethanolamine, n-hexylamine, n-heptylamine, n-octylamine,n-nonylamine, ethylenediamine, N,N,N′,N′-tetramethylethylenediamine,tetramethylenediamine, hexamethylenediamine,4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether,4,4′-diaminobenzophenone, 4,4′-diaminodiphenylamine, formamide,N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide,N,N-dimethylacetamide, propionamide, benzamide, pyrrolidone,N-methylpyrrolidone, methylurea, 1,1-dimethylurea, 1,3-dimethylurea,1,1,3,3,-tetramethylurea, 1,3-diphenylurea, imidazole, benzimidazole,4-methylimidazole, 8-oxyquinoline, acridine, purine, pyrrolidine,piperidine, 2,4,6-tri(2-pyridyl)-S-triazine, morpholine,4-methylmorpholine, piperazine, 1,4-dimethylpiperazine,1,4-diazabicyclo[2.2.2]octane, pyridine and the like. These may be usedalone, or in combinations of two or more thereof.

The (D1) nitrogen-containing compound may be used in an amount typicallyin the range of 0 to 5 parts by mass, and particularly in the range of 0to 3 parts by mass, with respect to 100 parts by mass of total mass ofthe (B) resin and the (C) alkali-soluble resin.

[(D2) Organic Carboxylic Acid or Oxo Acid of Phosphorus or DerivativeThereof]

Among the (D2) organic carboxylic acid, or the oxo acid of phosphorus orthe derivative thereof, specific preferred examples of the organiccarboxylic acid include malonic acid, citric acid, malic acid, succinicacid, benzoic acid, salicylic acid and the like, and salicylic acid isparticularly preferred.

Examples of the oxo acid of phosphorus or derivatives thereof includephosphoric acid and derivatives such as esters thereof such as, e.g.,phosphoric acid, phosphoric acid di-n-butyl ester, and phosphoric aciddiphenyl ester; phosphonic acid and derivatives such as esters thereofsuch as, e.g., phosphonic acid, phosphonic acid dimethyl ester,phosphonic acid di-n-butyl ester, phenylphosphonic acid, phosphonic aciddiphenyl ester, and phosphonic acid dibenzyl ester; and phosphinic acidand derivatives such as esters thereof such as, e.g., phosphinic acidand phenylphosphinic acid; and the like. Among these, phosphonic acid isparticularly preferred. These may be used alone, or in combinations oftwo or more thereof.

The (D2) organic carboxylic acid, or the oxo acid of phosphorus or thederivative thereof may be used in an amount typically in the range of 0to 5 parts by mass, and particularly in the range of 0 to 3 parts bymass, with respect to 100 parts by mass of total mass of the (B) resinand the (C) alkali-soluble resin.

Moreover, in order to form a salt to allow for stabilization, the (D2)organic carboxylic acid, or the oxo acid of phosphorous or thederivative thereof is preferably used in an amount equivalent to that ofthe (D1) nitrogen-containing compound.

The photosensitive composition contains an (S) organic solvent, forexample, for the purpose of preparing coatability. There is noparticular limitation on the (S) organic solvent as long as the objectsof the present invention are not impaired, and an organic solventappropriately selected from those conventionally used for positive-typephotosensitive resin compositions can be used.

Specific examples of the (S) organic solvent include ketones such asacetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone, and2-heptanone; polyhydric alcohols and derivatives thereof, likemonomethyl ethers, monoethyl ethers, monopropyl ethers, monobutyl ethersand monophenyl ethers, such as ethylene glycol, ethylene glycolmonoacetate, diethylene glycol, diethylene glycol monoacetate, propyleneglycol, propylene glycol monoacetate, dipropylene glycol and dipropyleneglycol monoacetate; cyclic ethers such as dioxane; esters such as ethylformate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate,butyl acetate, methyl pyruvate, methyl acetoacetate, ethyl acetoacetate,methyl pyruvate, ethylethoxy acetate, methyl methoxypropionate, ethylethoxypropionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate,ethyl 2-hydroxy-2-methylpropionate, methyl 2-hydroxy-3-methylbutanate,3-methoxybutyl acetate and 3-methyl-3-methoxybutyl acetate; aromatichydrocarbons such as toluene and xylene; and the like. These may be usedalone, or as a mixture of two or more thereof.

There is no particular limitation on the content of the (S) organicsolvent as long as the objects of the present invention are notimpaired. In a case where a photosensitive resin composition is used fora thick-film application in which a photosensitive resin layer obtainedby the spin coating method and the like has a film thickness of 10 μm ormore, the (S) organic solvent is preferably used in a range where thesolid content concentration of the photosensitive resin composition is20 to 70% by mass, preferably 30 to 55% by mass.

<Method of Preparing Chemically Amplified Positive-Type PhotosensitiveResin Composition>

A chemically amplified positive-type photosensitive resin composition isprepared by mixing and stirring the above components by the commonmethod. Machines which can be used for mixing and stirring the abovecomponents include dissolvers, homogenizers, 3-roll mills and the like.After uniformly mixing the above components, the resulting mixture maybe filtered through a mesh, a membrane filter and the like.

<<Method of Manufacturing Resist Pattern>>

The resist pattern using the photosensitive composition described abovemay be formed by any method without particular limitation, and apreferred method comprises laminating a photosensitive resin layer on asubstrate, the layer comprising the photosensitive resin composition,exposing the photosensitive resin layer through irradiation with anactive ray or radiation, and developing the exposed photosensitivelayer.

Examples include substrates for an electronic part, those on which apredetermined wire pattern is formed and the like. Examples of thesubstrate include substrates made of metals such as silicon, siliconnitride, titanium, tantalum, palladium, titanium-tungsten, copper,chromium, iron, and aluminum; and glass substrates. Examples of thematerial used for the wiring patterns include copper, solder, chromium,aluminum, nickel, and gold.

The photosensitive resin layer is laminated on the substrate, forexample, by the following method. Specifically, a liquid photosensitiveresin composition is coated onto a substrate, and the coating is heatedto remove the solvent and thus to form a photosensitive layer having adesired thickness. The thickness of the photosensitive layer is notparticularly limited. The thickness of the photosensitive resin layer isnot particularly limited, but is preferably 10 to 150 μm, morepreferably 20 to 120 μm, particularly preferably 20 to 100 μm.

As a method of applying a photosensitive resin composition onto asubstrate, those such as the spin coating method, the slit coat method,the roll coat method, the screen printing method and the applicatormethod can be used. Pre-baking is preferably performed on aphotosensitive resin layer. The conditions of pre-baking may differdepending on the components in a photosensitive resin composition, theblending ratio, the thickness of a coating film and the like. They areusually about 2 to 60 minutes at 70 to 150° C., preferably 80 to 140° C.

The photosensitive resin layer formed as described above is selectivelyirradiated (exposed) with an active ray or radiation, for example, anultraviolet radiation or visible light with a wavelength of 300 to 500nm through a mask having a predetermined pattern.

Low pressure mercury lamps, high pressure mercury lamps, super highpressure mercury lamps, metal halide lamps, argon gas lasers, etc. canbe used for the light source of the radiation. The radiation may includemicro waves, infrared rays, visible lights, ultraviolet rays, X-rays,γ-rays, electron beams, proton beams, neutron beams, ion beams, etc. Theirradiation dose of the radiation may vary depending on the constituentof the photosensitive resin composition, the film thickness of thephotosensitive resin layer, and the like. For example, when an ultrahigh-pressure mercury lamp is used, the dose may be 100 to 10,000mJ/cm². The radiation includes a light ray to activate the (A) acidgenerator in order to generate an acid.

After the exposure, the diffusion of acid is promoted by heating thephotosensitive resin layer using a known method to change the alkalisolubility of the photosensitive resin layer at an exposed portion inthe photosensitive resin film.

Subsequently, the exposed photosensitive resin layer is developed inaccordance with a conventionally known method, and an unnecessaryportion is dissolved and removed to form a predetermined resist pattern.

At this time, an alkaline aqueous solution is used as a developingsolution.

As the developing solution, an aqueous solution of an alkali such as,for example, sodium hydroxide, potassium hydroxide, sodium carbonate,sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine,n-propylamine, diethylamine, di-n-propylamine, triethylamine,methyldiethylamine, dimethylethanolamine, triethanolamine,tetramethylammonium hydroxide, tetraethylammonium hydroxide, pyrrole,piperidine, 1,8-diazabicyclo[5.4.0]-7-undecene or1,5-diazabicyclo[4.3.0]-5-nonane can be used. Also, an aqueous solutionprepared by adding an adequate amount of a water-soluble organic solventsuch as methanol or ethanol, or a surfactant to the aqueous solution ofthe alkali can be used as the developing solution.

The developing time may vary depending on the constituent of thephotosensitive resin compositio, the film thickness of thephotosensitive resin layer, and the like. Usually, the developing timeis 1 to 30 min. The method of the development may be any one of aliquid-filling method, a dipping method, a paddle method, a spraydeveloping method, and the like.

After development, it is washed with running water for 30 to 90 seconds,and then dried with an air gun, an oven and the like. In this manner, aresist pattern can be produced.

<<Method of Manufacturing Substrate with Template>>

In a substrate with a template for forming a plated article, a resistpattern formed with a photosensitive resin composition is used as atemplate. A nonresist section in the resist pattern is filled with metalby plating to form a plated article.

When forming a substrate with a template, a metal substrate is used as asubstrate. Note that in the metal substrate, the material of a surfaceon which a plated article is formed is to be a metal. Therefore, themetal substrate may be made entirely of a metal, or at least a portionof the surface on which a plated article is formed is made of a metal.As examples of a preferred metal as a material of a substrate, copper,gold and aluminum are preferred, and copper is more preferred.

The substrate with the template can be manufactured by a method similarto the aforementioned method of manufacturing a thick resist patternexcept that the above metal substrate is used as a substrate, and theshape of a nonresist section in the resist pattern is designed accordingto the shape of a plated article.

<<Method of Manufacturing Plated Article>>

A conductor such as a metal may be embedded, by plating, into anonresist section (a portion removed with a developing solution) in thetemplate formed by the above method on the substrate to form a platedarticle, for example, like a contacting terminal such as a bump or ametal post. Note that there is no particular limitation on the method ofplate processing, and various conventionally known methods can be used.As a plating liquid, in particular, a solder plating liquid, a copperplating liquid, a gold plating liquid and a nickel plating liquid aresuitably used. Finally, the remaining template is removed with astripping liquid and the like in accordance with a conventional method.

In the above method of manufacturing a plated article, the platedarticle is formed using a template comprising a nonresist section havinga good rectangular cross-sectional shape and formed with aphotosensitive resin composition. Therefore, the cross-sectional shapeof the plated article formed will also have a good rectangular shape.

EXAMPLES

Below, the present invention will be described in more detail withreference to Examples, but the present invention shall not be limited tothese Examples.

Examples 1-8 and Comparative Examples 1-3

In the Examples and Comparative Examples, the following compounds wereused as the (A) acid generator.

In the Examples, resins P-1 to P-8 specified in Table 1 were used as the(B) resin whose solubility in alkali increases under the action of acid.In the Comparative Examples, resins P-9 to P-11 specified in Table 1were used as the (B) resin whose solubility in alkali increases underthe action of acid. The constitution of the constituent units in theresins P-1 to P-11 is indicated below as A to I. Numerical valuesindicated at lower right of each constituent unit refer to theproportion (% by mass) of the constituent units in the resin.

TABLE 1 Constitution of Mass average Dispersivity the constituent unitsmolecular weight (Mw) (Mw/Mn) P-1 A 38,000 2.65 P-2 B 42,000 2.41 P-3 C42,000 2.72 P-4 D 39,000 2.70 P-5 E 44,000 2.56 P-6 F 40,000 2.73 P-7 C103,000 3.25 P-8 C 27,000 2.07 P-9 G 45,000 2.80 P-10 H 44,000 2.98 P-11I 37,000 2.64

In Examples and Comparative Examples, tri-n-pentylamine was used as anacid diffusion control agent.

Photosensitive resin compositions were obtained by dissolving 100 partsby mass of the resin specified in Table 2, 2 parts by mass of the acidgenerator, and 0.02 parts by mass of the acid diffusion control agent inpropylene glycol monomethyl ether acetate to give a solid concentrationof 53% by mass. For the photosensitive resin compositions thus obtained,the sectional shape, resolution and sensitivity of the nonresist portionin the resist pattern were evaluated according to the following method.

[Evaluation of Sectional Shape in Nonresist Portion]

The photosensitive resin compositions of Examples 1 to 8 and ComparativeExamples 1 to 3 were coated onto an 8-inch copper substrate with a spincoater to form a photosensitive resin layer having a thickness largeenough to form a 100 μm-thick resist pattern. The photosensitive resinlayer was prebaked at 150° C. for 5 min. After the pre-baking, patternexposure was carried out by ghi ray using a mask having a hole patternfor the formation of a hole pattern having a diameter of 60 μm and anexposure device Prisma GHI (Ultratech Inc.). Subsequently, the substratewas mounted on a hot plate to perform post-exposure baking (PEB) for 3min at 100° C. Then, a 2.38% aqueous solution of tetramethylammoniumhydroxide (TMAH) was added dropwise to the photosensitive resin layerand was allowed to stand for 60 sec at 23° C. This procedure wasrepeated 4 times for development. Thereafter, washing with running waterand blowing with nitrogen were carried out to obtain a resist patternhaving a contact hole pattern with a diameter of 60 μm.

A cross-section perpendicular to the plane direction of the resistpattern in a nonresist portion (hole) in the resist pattern formed wasobserved using a scanning microscope, and the maximum diameter CD_(max)and the minimum diameter CD_(min) of holes corresponding to the surfaceof the substrate were measured. The sectional shape of holes wasevaluated by CD_(max)/CD_(min) values based on the following criteria.The sectional shape of the hole is of a more favorable rectangle as thevalue of CD_(max)/CD_(min) is closer to 1. The results of evaluation forsectional shapes of nonresist portions are shown in Table 2.

Very Good: CD_(max)/CD_(min) is less than 1.1.Good: CD_(max)/CD_(min) is 1.1 (inclusive) to 1.2 (exclusive).Fair: CD_(max)/CD_(min) is 1.2 (inclusive) to 1.3 (exclusive).Bad: CD_(max)/CD_(min) is 1.3 or more.

[Evaluation of Resolution]

Contact hole patterns were formed to evaluate the resolution in the samemanner as described above in connection with the method of evaluatingthe sectional shape of the nonresist portion, except that three types ofmasks for the formation of hole patterns with 20 μmø, 40 μmø, and 60 μmøwere used. The resolution was evaluated based on the following criteria.The results of evaluation of the resolution are shown in Table 2. ForComparative Example 2, holes with 60 μmø could not be formed.

Very Good: Resolution of holes with 20 μmø was possible.Good: Resolution of holes with 20 μmø was impossible although resolutionof holes with 40 μmø was possible.Bad: Resolution of holes with 40 μmø was impossible.

[Evaluation of Sensitivity]

Contact hole patterns were formed with masks for the formation of holepatterns with 100 μmø while varying exposure dose in the same manner asdescribed above in connection with the method of evaluating thesectional shape of the nonresist portion. In this case, the exposuredose at which resolution of holes with 100 μmø was possible was regardedas sensitivity. The results of evaluation of sensitivity are shown inTable 2.

TABLE 2 Resin Evaluation of (Type/ sectional shape Parts by in nonresistEvaluation of Sensitivity mass) portion resolution (mJ/cm²) Ex. 1P-1/100 Good Very Good 300 Ex. 2 P-2/100 Good Very Good 500 Ex. 3P-3/100 Very Good Very Good 500 Ex. 4 P-4/100 Good Good 1500 Ex. 5P-5/100 Good Very Good 900 Ex. 6 P-6/100 Very Good Very Good 500 Ex. 7P-7/100 Very Good Good 700 Ex. 8 P-8/100 Very Good Very Good 300 Comp.Ex. 1 P-9/100 Bad Bad 500 Comp. Ex. 2 P-10/100 Bad Bad — Comp. Ex. 3P-11/100 Bad Bad More than 2000

Examples 1 to 8 demonstrate that, when a photosensitive resincomposition comprising an (A) acid generator that produces an acid bybeing irradiated with an active ray or radiation, a (B) resin whosesolubility in alkali increases under the action of acid, and an (S)organic solvent, wherein the (B) resin comprises an (B-3) acrylic resincomprising a constituent unit derived from an acrylic acid estercomprising an —SO₂-containing cyclic group or a lactone-containingcyclic group and a constituent unit derived from an acrylic acid estercontaining an organic group comprising an aromatic group and analcoholic hydroxyl group, is used, a resist pattern comprising anonresist portion having a favorable rectangular sectional shape can beformed.

Comparison of Comparative Example 1 with Example 3 reveals that, whenthe (B) resin does not contain a constituent unit derived from anacrylic acid ester comprising an —SO₂-containing cyclic group or alactone-containing cyclic group, a resist pattern comprising a nonresistportion having a favorable rectangular sectional shape is unlikely to beformed, and the resolution decreases.

Comparison of Comparative Example 2 with Example 3 reveals that, whenthe (B) resin contains a constituent unit derived from an acrylic acidester containing an alcoholic hydroxyl group and without containing anaromatic group, instead of the constituent unit derived from an acrylicacid ester comprising an organic group containing an aromatic group andan alcoholic hydroxyl group, the resolution is significantlydeteriorated, making it difficult to favorably form a pattern per se.

Comparison of Comparative Example 3 with Example 3 reveals that, whenthe (B) resin contains a constituent unit derived from an acrylic acidester containing an aromatic group and without containing an alcoholichydroxyl group, instead of the constituent unit derived from an acrylicacid ester comprising an organic group containing an aromatic group andan alcoholic hydroxyl group, the resolution is significantlydeteriorated, making it difficult to form a resist pattern comprising anonresist portion having a favorable rectangular sectional shape.

What is claimed is:
 1. A chemically amplified positive-typephotosensitive resin composition, comprising: (A) an acid generator thatproduces an acid by being irradiated with an active ray or radiation;(B) a resin whose solubility in alkali increases under the action ofacid; and (S) an organic solvent, wherein the (B) resin whose solubilityin alkali increases under the action of acid contains an alkali-solublegroup protected by an aliphatic acid-dissociable dissolution-inhibitinggroup, and comprises an (B-3) acrylic resin comprising a constituentunit derived from an acrylic acid ester comprising an —SO₂-containingcyclic group or a lactone-containing cyclic group, and a constituentunit derived from an acrylic acid ester containing an organic groupcomprising an aromatic group and an alcoholic hydroxyl group.
 2. Thechemically amplified positive-type photosensitive resin compositionaccording to claim 1, wherein the constituent unit derived from anacrylic acid ester containing an organic group comprising an aromaticgroup and an alcoholic hydroxyl group is represented by the followingformula (b-H1):

wherein, in the formula (b-H1), R represents a hydrogen atom, an alkylgroup having 1 to 5 carbon atoms, or a halogenated alkyl group having 1to 5 carbon atoms; R^(18b) represents a linear or branched aliphatichydrocarbon group having 2 to 20 carbon atoms; and R^(19b) represents anaromatic hydrocarbon group.
 3. The chemically amplified positive-typephotosensitive resin composition according to claim 1, wherein theproportion of the mass of the (B-3) acrylic resin to the total mass ofthe resin component contained in the chemically amplified positive-typephotosensitive resin composition is not less than 70% by mass.
 4. Thechemically amplified positive-type photosensitive resin compositionaccording to claim 1, wherein said composition is used to prepare atemplate for plated article formation on a metal substrate.
 5. A methodof manufacturing a resist pattern, comprising: laminating aphotosensitive resin layer on a substrate, the layer comprising thechemically amplified positive-type photosensitive resin compositionaccording to claim 1; exposing the photosensitive resin layer throughirradiation with an active ray or radiation; and developing the exposedphotosensitive layer.
 6. A method of manufacturing a substrate with atemplate, comprising: laminating a photosensitive resin layer on a metalsubstrate, the layer comprising the chemically amplified positive-typephotosensitive resin composition according to claim 4; exposing thephotosensitive resin layer through irradiation with an active ray orradiation; and developing the exposed photosensitive layer to prepare atemplate for plated article formation.
 7. A method of manufacturing aplated article, comprising plating the substrate with a templatemanufactured by the method according to claim 6 to form the platedarticle inside the template.